[FooBarWidget]

Libraries can be done, but that has got nothing to do with momentum. Momentum depends on mindshare, on the willingness of people to use and to keep using it. Most programmers don't choose technology based purely on merits, they choose it based on "I heard X talk about Y and s/he said good things, so I guess I'll use it". We programmers aren't as rational as we think.

[sanderjd]

Like it or not, popularity and momentum are important merits of a technology. They lead to all sorts of benefits, like healthy maintenance and further development, better documentation, and support when you run into trouble. It is rational to consider these things when choosing technology.