[EpicEng]

Because, for those projects who want a thriving userbase, the developers said "come, use our software to solve your problems." Once you do that you are making a promise to your users, whether explicit or implicit, that you'll be there when things go wrong.

If you release some script or small program which was useful to you thinking that it may help someone else down the road, I agree, you don't owe your users anything. However, when you position your solution as something people should adopt (e.g. RoR, etc) then you do owe a level of quality and support to your users (not saying RoR doesn't, just a random example.)

I love OSS, but every time it bites a user in the behind it loses mindshare.