I haven't read all the posts, but I thought I'd add my experience as a data point. I've ridden around 25,000 miles on tubeless tires in about two and a half years. Maintenance over that time? ZERO. Well, that's not true. I did try to plug a well-used tire with a pretty significant puncture that was sealing on it's own, but that I was afraid would later fail. The plug didn't go well, making the puncture worse. That tire probably had at least another 1-2k miles of life left in it but I decided to go ahead and replace it.
Now that I think about it, I did replace the rim tape on a set of wheels when I changed tires once. But I didn't really *need* to.It took about 45 minutes, all told.
I've never had to add sealant, but I run through a set of tires every 4-5 months...it usually doesn't have time to totally dry up. As far as tire life goes, I get about 5,000 miles out of a pair of GP500TLs in 32mm. I could get more out of the front, but I just replace them as a pair.
Edited to add pressure info. I'm a big guy. I've run pressure as high as 90 pounds. Currently running 55F/60R.