you cant kill a good game that easy, heck i probly wont start playing R.Fom online for another week, and besides good games can stay around for a long time exspecially on the p.c. People still play diablo on a regualar basis, and i play an old game avp2 at least once a weak.
Even if some people are diverted from playing R.Fom as more games come out more and more people will be buying the ps3 now that the price has droped again and as long as it doesnt get overrun with hackers i would predict it should have a good population of great players for quite some time