In comments to his quit post, Coburn answered Owen's questions about the reason thus:

I’m not sure if there’s any single thing. To some extent I’ve often been on the verge of quitting, only to pull myself back for some reason or another. It seems like quite a big effort to go to, and honestly looking the end product I’m kind of ambivalent. I guess the strange death of OH played its part in making me assess what it was I really wanted to be doing too.

The website is up, and the last post was two weeks ago.

Developing...

BTW, I remement a case of a Fedora contributor Ignacio Vazquez suddenly disappearing in 2006. He got people worried. But then he suddenly reappeared 9 months down the road. Most likely Riex is not decomposing in a public park.