Wow, this thread is getting serious isnt it?
I think the points that everyone have made are valid, especially when it comes to risks. But, to some degree, what Ethan was saying about programmers not willing to take risks, large or small, I have to agree with also ( if you have several months spare for listening to Ethan, then ask him to give you examples of programmers who don't take risks
).
MMOs are MASSIVE projects, no doubt about it. They take time, effort, money and man-power. We all know this, it's stating the obvious. Speaking from my small amount of experience, I have been on the development team for two MMOs in the last 10 years, the first one being my own personal project which I designed, planned, built a team for and got a basic skeleton of an MMO up and running and learnt as I went along.
The second one though, was the biggest challenge I have ever taken on in my life. I offered to help out for free because I needed programming experience. It was that job that taught me how to program, even though I definitely couldn't see me handling bigger tasks on that project. Yes, I am not a brilliant programmer, but I know enough. The five years I was on that job, I was learning as I was going along and I had my own day job too, so I wasn't even on the project full-time, just the 'couple of hours a week guy' that Ethan mentioned.
What I learnt, what code I wrote, what I saw I was capable of, is beyond anything I ever dreamed. I learnt how to write networking code and even integrated it into a commercial game engine. Sure, I made mistakes, it took time, it was very difficult, but I got there.
As many have said in this topic, there are major risks, and mostly to the project and its designer but I don't think it is the biggest problem some programmers have with MMOs. Speaking personally, I think it is the amount of time you will spend learning, making mistakes, correcting your mistakes and making some progress with the MMO that is the hardest problem. It will take longer than a single player, 2D or 3D platformer, top-down shooter etc to build and it seems impossible to most people anyway. Even I don't think I can single-handedly build an MMO, but it is worth it.
But, if you want to be a better programmer, can learn on the job and have a little time available, try it, because there is little risk to you and like me, you might be surprised what you learn. I am not saying that if you want to be a better programmer and can learn on the job that working on an MMO is the only way to go, it is just an option that I don't feel anyone should avoid because they don't think they are capable enough.
I could talk about this subject for hours, so I think i'll stop there. Look forward to hearing everyones thoughts.