It didn't seem to take very long to me, but it can vary. AIR in 100 scrolls of wishing I got about 4 bottles of antidote (and the time on getting all those bottles can be shortened by just dropping that silly encrypted scroll and doing r <enter> <enter> after the first wish). There is the alternate idea of cloning wands, but I think that might actually take longer due to typing in wishes.
I remember when I thought wands of polymorph were enemy-only (too used to Crawl's wand of polymorph other); finding out they were much better for utility purposes was something else.
Artificial limbs also cannot improve their stats. Scrolls of change/harden material and god favor are all you can make use of to try and get better materials for said limb (you can also lop off the limb in question and drink healing liquid for new human limbs, but depending on how long you had that for it could be rather more drastic and disastrous than you bargained for). This basically means that unless your new limb is considerably more powerful than your old one it may *not* be such a good idea to keep your limb that way (although SOCMs, with enough Int, can fix such material mistakes).
All of them? I'm pretty confident not even half or a quarter of them are dead. Mostly since the impression I've gotten is that developing roguelikes is a 20/30-something gig, not something you do when you are 60 or older. Much more likely that they found some real-life activities like a regular job, taking care of family, and stuff like that which was more fulfilling/necessary than working on a roguelike.
Oddly enough I'm getting an occasional "forum/viewforum.php does not exist" error. Clicking the link to the main forum page seems to fix it, but it keeps popping up.