Sure, sure. It's just odd to single out the Persona statement to me, by most measures that aren't "compare them straight up to a Final Fantasy/Bioware/Bethesda game" they're quite successful as RPGs go. Two games that between them have had five releases, three spinoffs (with another on the way) and adaptations of all sorts since their original release.
There are plenty of bigger JRPGs released in the past decade, but most of them have the title Final Fantasy, Dragon Quest, Kingdom Hearts, or Pokemon. If you disqualify all of those for various reasons, there's also Fire Emblem: Awakening. Dark Souls is sometimes considered one as well, so obviously that too if you do.
I would honestly expect that, again limiting ourselves to "the entries in the series released after 2005", Persona 4 actually has outsold each of the four Kingdom Hearts games individually, and most likely FE13 although that's closer. DQIX vs Persona 4 would be a number I'm interested in, I imagine DQIX is weaker than any game previously mentioned here but I could definitely be wrong. Two FF games have been released in that time frame (omitting FFXIV, it's a different genre), both are sufficiently divisive that whether they could make the list is debatable, although obviously they are more widely played.
I kinda mentally omit Pokémon from these discussions, though, couldn't tell you why. Although from Scar's comments apparently this is common.
e: For reference, I'm guessing worldwide sales for the various games here as 300k for KH:reCoded, 500k for FE13 and KH:DDD, 700k for DQIX, ~1M for KH:358 Days and BbS, ~1.3M for Persona 4, 5-6M for the Final Fantasies. And like 3M per version of Pokemon of course. If P4 didn't get a European release though you're probably right and it'd be more like 8-900K.