SMB, Tetris, etc., were different because you had the option to buy the system without them; they were just good deals.
Err...no you couldn't, at least not for the first year or two of sales (and presumably Wii Sports will be de-bundled eventually).
I agree that their own placement is grossly overrated but there's still justification to it; Wii Sports sales hype is worth almost as little as Minesweeper sales hype, or sales hype for that demo disc that came with my PSX.
Super Mario Bros. is an intensely important game that is still notable two decades later; I can't imagine you'll be able to say the same for Wii Sports in 2030.
Err...how closely have you been watching the market? It's very noticeable that the Wii games that make top 10 sales are very consistently ones that come with some controller add-on. Wii Fit. Wii Play. Mariokart Wii w/ Wheel. Guitar Hero. Rock Band. Notably, stuff like Smash Bros and Super Mario has not stayed on the top 10. Notably, Guitar Hero and Rock Band sell better on Wii than on 360/PS3, whereas other third party games are the exact opposite.
For that matter, I remember looking at Youtube videos of people playing Wii a few months after it came out. 90% of them were Wii Sports, not Zelda TP (or whatever the other competition was at the time). Stories of the Wii being very popular among Senior's centers that had previously never touched a console, or being used in hospitals for health purposes--again the game in question was Wii Sports. A 40-something British coworker of mine was still playing Wii Sports several months after the Wii came out (using it as a work-out).
Frankly, Wii Sports is the pretty obvious most influential game of this generation. That doesn't mean I have to like it. I'll happily admit that GTA3 was the most influential game of last generation, and yet the very concept of GTA3 holds no interest to me.