I also think that it's vastly underestimated the strength of the response that people have when something previously run by volunteers is made for-profit, or where it is expected that the community financially support a couple of professional staff. Having been through that conversion process--it is very ugly. You run the risk of turning off some of your best and most loyal supporters and audience for a new one (which is fine, sometimes it needs to be done).
So it's very important to weight the losses that you will invariably have for the gains you will make. Yes, it would be great to get more under 30s in. Are you willing to say "fuck you bye!" to a huge amount of older people who have been the mainstay and who have been involved for decades, for people you aren't sure will stay out the year, just for the sake of improving your game demographics?
What problem are you trying to solve by monetizing or encouraging monetizing as a whole? Will this lower or raise the barriers to entry both for the person trying out the hobby, and the problems faced by game creators or potential game creators?
The truth is, that while it is important to get new blood in, it's actually pretty important to keep old blood in too. Might not want to shit too much on the nostalgia/current players, in the hopes that you might somehow find the formula to bring in a handful of extra younger people (who may or may not be great assets to the community, just like everyone else).
Personally out of all the ideas here, I think someone creating a MUSH with a theme that younger folks would recognize/respond to is the best one. I know a ton of young players that started trying out new-to-them but old fogey themes because they really got into mushing based on something that they did like.
Also, frankly, 20 somethings are not aliens from another planet who can't relate to older people or who are less capable of trying new things? It doesn't mean we can't/shouldn't adapt to the tools we have now (AGAIN THANK YOU FARADAY, even 10 years ago I /never/ would have thought I'd be able to be working on my own place, and now that is a goal that I can actuall achieve), I love all the incorporation of web based stuff on Arx, ect.
I think continuing those innovations and empowering the young folks IN the hobby to set up /the games with themes that they would like to see/ (and checking them out/supporting/playing there when it happens) might be the best way to get more people in. Rather than thinking they need to be spoonfed. In my experience, they need it less than older people.