I didn't donate and managed to win Kanto and Johto Elite Four at the first try.
Besides, membership only pokemons are often non-ms few areas further in the game, and as they are rare, and you don't have time to lvl up your pokés, you wouldn't have the time to find the ms-only one either :)
You'll have to take the time, appreciate the game as its given, enjoy the fact that it is a MMO to meet friendly players and have fun with them, otherwise, as Sesshomaru said, an offline ROM would suits you better (even if some of them, e.g. pokemon gemme, are harder than official released versions)