I'm not sure what you mean by "no more large multiplayer RPGs" here. It's not technically impossible to have community-hosted MMO servers. Hell, most MMORPG publishers have to have an active legal team specifically to shut those down.

As for community run servers being longer to develop... wait, what? How is that the case, when that used to be the standard way multiplayer got built prior to everyone trying to chase World of Warcraft? I can understand the anti-cheat argument, and I will begrudgingly acknowledge that you can't exactly force third-party servers to run your anti-piracy checks. But none of that is a technical argument. That's an argument about business risks, and publishers all jumped on the live service bandwagon because they consider their customers' control over their own games to be a business risk.