Because many of the players are attached to the first generation, having so many memories from their childhood. And having outgrown childish things while still being attached to apart of it would mean liking only the ones that they know and love.
That aside, I think 4th Generation sucks because the pathetic pokemon....seriously:
=Wannabe list=
Bidoof - Rattata
Bibarle - Radicate (Sorry for spelling, I don't know half of them)
Starly through Staravia - Pidgey through Pidgeot
Beautifly, Dustox and all of their previous evolutions - COMMON SENSE
And probably MANY more.
Not to mention all the additions to good pokemon such as Magmar and Electabuzz (and Eevee). If you want to talk about story how would you explain them never being able to evolve fully in times when the evolutions didn't exist.
Regarding the posts on story and franchise:
When you think of a Pokemon game do you think of story?? Isn't it all pretty much the same? Get your first pokemon from the professor, go collect gym badges, beat the elite four, and while doing this face your oh-so-original rival? I'm not so sure on franchise though, but what does that have to do with the pokemasters (we know who we are lol) hating the 4th season? When the little 6-8 year olds grow up and hate like the 8th season, I figure they'll understand why.
1st Gen FOREVER
-2G+PN