Right, after nearly 7 months I can give out some information.
First of all, I've positively 'unmaintained' this module. I've heard this can cause problems with the Upgrade module. This can be switched out at admin/logs/updates/settings. See this page for someone else who has taken this step.
Quite a while ago now I left an enigmatic message saying I would be away for a while, but hoped to stay in touch. I couldn't even manage that basic support, for the simple reason I had no computer. I had no home either, but that's a peripheral, I guess.
I'm in no position to be a maintainer now. I'm left with one small computer and can't cross-browser test or, at the moment, even step debug. It takes me 15 mins just to run Theme Developer, and ... what the heck, you get the idea.
I never had the best computing facilities, but I knew I was answering a need and did pretty well in the end. The fact several of my ideas have been taken up round the community sort of shows that, though I've found the lack of accreditation discouraging (Taxonomy Menu guys get a small exception here). And the fact that, despite initial scorn (coders, not site designers) Taxonomy Treemenu is plainly on a lot of folks wishlists.
Not only the computing facilities, but the will has gone. Plenty of ex-maintainers seem to fudge this issue or glance over it. Taxonomy Treemenu was me scratching an itch. It was a release to dip away for a couple of hours and work on it. Especially as, I don't know why, but we just had the friendliest, most progressive issue queue here.
Now I find I find myself at least free, but in reduced circumstances. I have to ask myself, what can Drupal do? I took a month out to see, which became two months, and I turned out plenty of software as a result, but can't guarantee a standard for Drupal site releases.
This is the end of my involvement for now.
In another context, I've already taken some flack for not being 'public spirited'. The page linked above has this to say,
"You cannot use open source in a bubble by yourself and be successful. You must not only share, but get others to use your module too so they have a shared interest in getting it upgraded as Drupal grows."
Great. Opinions welcome. But do attach your annual salary and then I can rank your indignation.
I'd like to give thanks for all the great posts on the queue, and to the people I swapped ideas with. It was a pleasure to meet you (in a web-like fashion), and I'm going to miss that.