I don't believe I claimed Twitter was not under active development. The point that I was making here is that if we were OK with Twitter as-is, it would be possible to maintain it with far fewer people than they employ now. Indeed, 'maintenance' will be defined differently for an indie hacker vs. a popular website with user-generated content. But all software has some split of "keeping the lights on" vs. innovating.

What is your estimate of Twitter's effort split between those two categories?