TJ had already written every module possible in Node so he moved on to rewrite them all again in Go. He'll do the same once he's exhausted all Go modules there are to write.

Suffice to say his exit hasn't changed anything, his efforts have been taken over by others and NPM is still growing at a fast rate.

When I read your post I thought "What? I'm using Koa right now and it's maintained by TJ" but the post says it's the only one haha.

Did anything of this change after IO.js was forked?