Not sure about that. From what I remember in the stores at the time the Megadrive, in the UK at least, always seemed to have more games in the stores. The Megadrive might even had seen more overall releases. However I would agree that the SNES saw more AAA releases in the end.

I also picked the SNES myself, because at the time the Megadrive felt to me like a console version of the 16 bit computers on the market, whereas the SNES felt like Nintendo really did go all out to design a pure gaming system that was not worried about the home computers around at the time. Gameplay and graphics in SNES games were also always more consistently good, whereas with the Megadrive, it was very hit and miss, again much like the home computer market.

The Megadrive did see some brilliant ports of SEGA arcade games and Sega's own games for the system. Plus quite a few great third party releases, but the SNES had something special about its feel, just like all Nintendo consoles seem to. I also think the SNES hasn't dated badly and its games are generally just as playable today.