There is no professional company who is going to deliver professional product without getting paid. What they are looking at now is the amateur market, unless someone with spare burn like Google is going to take interest. (Probably the most effective way this could be done at this point is through a Google-MMO team partnership.) AFAIK this does not include any major game companies, and in particular any major MMO companies. MMOs are still indie enough because of the business model (you're dealing directly with customers/players, you're not shipping through a publisher upon whom you depend for your milestone payments) that they have to care about their day-to-day survival. So the people who know the most about this space are not going to be able to get involved for free. By virtue of the system they are setting up NASA is looking for people who are not the best at what they do, which is very sad, because they could easily have had the best in the business. The people that I know who submitted replies to the RFI were very put off by NASA's "just kidding" gotcha with this project and want nothing further to do with it. There may be others who didn't, but there is not currently a good model for success here. If it had been initially presented this way, it might be different, but now they've alienated professional teams by bait and switch, which is more damaging than if they'd never suggested the RFI in the first place.
It would have been very feasible to make a strong core MMO for $3 mill, build a space engine with physics and interesting core gameplay and art. Not from zero, though. Anyone who can make money at this is going to be doing things that make money, executing on THEIR dreams at a professional level of investment and business. They were eager to work with NASA, but NASA is not providing enough add to make this worthwhile any longer, and that's quite sad.
What they also seem to not understand is that it takes a pro team to execute on something like this. Thinking that you can charity/indie it for nothing or use the engineering resources available to NASA and not include a professional game developer is how you get the edutainment crash.