There are always exceptions of course - I believe both The Kingdom of Loathing (www.kingdomofloathing.com) and Love (www.quelsolaar.com/love) are products of individuals. Neither are typical MMOs, and both embrace different sorts of simplicity. KoL uses rudimentary (yet charming!) graphics and a rather clunky web interface, and Love's world is generated procedurally.

I think it is possible to bootstrap _certain_ types of "massively multiplayer" games, but with the necessity of making significant compromises in design.