In my humble opinion, the thing that would stop a lot of people from building there own MM, AFM, or other game would be the few parts that in the end would just prove unattainable. I agree with most here that state the parts could be fabricated. Speaking for myself, I do not have the time or skill to fabricate parts from scratch. Plus, if I did fabricate any parts, I suspect they would be of poor quality. I do have the skill, time, & space to assemble my own game. All I would need is the parts. I would want all the parts sourced before I would spend the first dollar.
That said, if someone took the time to put together the list of needed parts and where to get them from, I would buy a kit (or put together my own). I think in the end greed will get in the way. People fabricating parts for $25 will want $75 for them because they is not available anywhere else. If this happens enough, then it would be cheaper to buy an already restored game.