This.

Same with alternators.

Yeah it's looking more and more like a bad starter, which would be completely consistent with the way my luck has been running. And no, it wasn't necessarily a great replacement, it's a Duralast from Autozone. But so was the one I pulled out, and it lasted for 100k miles.

If it's not the starter then I'm getting too much resistance somewhere in the starter circuit, maybe with a bad ground somewhere, but I swear I've checked and doublechecked the grounds. I"m probably missing one somewhere.

Seems like I'd learn my lesson with cheap remans; Once I put 5 different starters in a CJ5 before I got one that worked.

Follow up from me on this thread (I just got back into town and was able to spend some time on the car). Following the logic that suggests that in the absence of a clear answer, the most logical solution is likely the correct solution, I went back to the ground strap. It sure looked fine but I took it off anyway, cleaned and sanded the contact points and secured everything nice and tight, and that did it.

I never would have guessed that a normal-looking and feeling ground point could bleed off 4 volts and prevent the starter from engaging, and that's why my car was down for so long. Live and learn.