I think outside of this site, most people play RPGs mainly for characters and story, and consider gameplay "whatever, as long as it's there and kinda fun" except in the case of specifically strategy games. Seeing someone classify Earthbound as a NON-experimental game is... very surprising to me.
You make a good point about most people's aims for RPGs, at least from the western POV. There certainly exist people outside the DL community who value gameplay over story and characters; Dragon's Den (the DQ fansite) and Insane Difficulty are pretty good examples of such communities. (Yes, some people really love DQ gameplay for its simplicity.) I would make the (completely unscientific) argument that average JRPG gameplay has gotten worse over time, with the caveat that while the *average* has gotten worse, the outlier games with fantastic gameplay have tended to get better and better. A game with otherwise extremely safe gameplay (like Dragon Quest) needs something to elevate it above that for *some* niche, and that something is usually either characters and story (see Earthbound or Wild Arms) or a semblance of difficulty (most actual Dragon Quest games). Neither one appeals to everyone, naturally. But I would submit that a game with typical early Dragon Quest-tier plot/writing, Dragon Quest-style combat, and difficulty comparable to your average FF game would generally not be very popular barring extraordinary circumstances, like being the only RPG on its console. (It sounds like I'm calling out Golden Sun, but GS plot is quite a bit above early DQ, surprisingly enough.) Conversely, FF games get away with how generally shallow their gameplay is because people love the characters, stories, and general spectacle.
Earthbound was certainly extremely experimental in its setting, writing, and characters, at least by JRPG standards (WRPGs had already long since toyed with wacky interpretations of real world settings, albeit usually in a post-apocalyptic light), but its gameplay is fundamentally indistinguishable from Dragon Quest with the serial numbers filed off outside of a few subtle nuances like the rolling HP meter.
It seems like you're really hyper-focused on a particular element of "gameplay" and trying to jam everything into a that interpretation. Where you say "gameplay" you really mean "the combat system." Yeah, combat systems have been de-emphasized in games, but it's because the growth in storage space and processing power has enabled additional forms of gameplay to emerge. If you use Skyrim as an example again, the actual combat is very pedestrian but there are many elements of gameplay that exist outside the combat engine that are just as engaging and often provide alternatives.
Is gameplay just combat? Or does it encompass exploration and world modification and general dickery? The fact that the results are not limited to Japanese products indicates that it's the latter.
You make a pretty good point there, and indeed the definition of what is "RPG gameplay" is something that's broadened quite a bit as technology has enabled it to. I do often tend to abstract it to mean "the combat system", yes, because especially with the older JRPGs, that is where the overwhelming majority of the meaningful gameplay is (especially notable pre-PSX or so). It isn't really until the PS2 era that you start seeing JRPGs other than Final Fantasy games break out of this mold in general, I feel; I certainly wouldn't count "exploration" as gameplay in the overwhelming majority of SNES RPGs as they simply have nothing notable (if anything at all) to find most of the time. You do see some sorts of non-combat gameplay starting to manifest through the SNES era, though; examples include Lufia 2's dungeon puzzles and, for a more extreme example, Inindo: Way of the Ninja's midgame shift in focus once the main character is hired by a daimyo. On the other end of the spectrum, of course, the classical example to pull up would be FF13, where (until you get to Gran Pulse, anyway) combat accounts for 100% of the meaningful gameplay.
Mentioning FF13 brings up another interesting point though: most RPG players at large are enamored with having the
illusion of exploration or choice, even if there is in fact nothing to find, or if the options you're given are all ultimately meaningless. One needs no greater evidence of this than comparing the fandom's reactions to FF10 and those to FF13; the latter game was criticized pretty heavily, on both sides of the ocean even from my understanding, for how oppressively linear the game is (almost all maps until Gran Pulse are singular corridors with maybe one or two branching paths with treasure, and there's no backtracking ever). FF13's fans, on the other hand, appreciate FF13 for how tightly balanced its combat is (especially by FF franchise standards, as this is typically a weakness of the franchise), and this is (as far as I've noticed) the predominant view of the game here in the DL community. I bring this comparison up, though, because FF10 is in fact almost exactly the same thing - the overwhelming majority of areas before the Calm Lands are strictly linear with the occasional branching path hiding treasure - and the Calm Lands are roughly about as far in the game as Gran Pulse is in FF13.
The only difference is that FF10 lets you backtrack (and in a few rare cases, you can gain things from doing so, even).
For an older example, we can even look at something like FF6, where the first half of the game (i.e. the World of Balance) is strictly linear to a fault. Meanwhile, the World of Ruin is completely nonlinear (although there is a vague intended progression reflected in the difficulty of the randoms) and has meaningful exploration gameplay as such - assuming the player is unspoiled and has no strategy guide or walkthrough, they need to explore the world to find their party members, and this is undoubtedly meaningful gameplay that isn't combat.
That said, there is at least some portion of FF6's fanbase (disclaimer: myself included) who feels that the World of Balance is the height of the game, and the quality of the gameplay quickly degrades in the second half, either because they don't care for the nonlinearity of the World of Ruin arc, or because they dislike how the game balance tends to break apart as you pick up the variously overpowered pieces of gear FF6 throws you in the World of Ruin and get the high-end spells and generally break the game over your knee. Even unspoiled, there are a LOT of ways to break FF6 and it's pretty hard not to stumble onto at least one of them. (And if you get lost enough in trying to find the party members unspoiled, you may well just end up horribly overleveled and break the game THAT way.) Simply put, character choice matters a lot more in the World of Balance, whereas by the World of Ruin, the individual abilities of the characters often become functionally irrelevant.
I'm not an expert on the subject (as I play very few WRPGs in general), but my general impression is that WRPGs in general have much more of these non-combat oriented kinds of gameplay. (I don't get all that excited about world modification, so many modern WRPGs simply don't appeal to me.) In the JRPG space, combat still comprises the majority of the gameplay in most of the games I've seen even in the more recent console eras, though notable exceptions like the later Persona games' time management/dating sim subgames or Atelier crafting systems definitely exist. I submit though that the majority of my JRPG experience is PS1 era and earlier, and I have a relatively small list of completed RPGs from PS2 and later, so I'm not the greatest authority on the direction of the genre of late.