I have had 5 Toyota trucks and only replace them because I get antsy every few years for the newest thing. Never had a single problem with one and my current 19 taco at 70k miles just feels like a break in period. Each time the trade is is quite close to what I paid for it. Have been looking at getting a late 80's 4runner as a fun second rig and don't anticipate any issues with that either.
If you had a torn cv boot, it was a 4x4. The cv doesn't actually transmit any power when you're in 2 wheel drive mode. So unless you did many miles in 4x4 after the torn cv boot, you wouldn't really ever experience a problem with it. That's very different than a FWD car with a torn boot.
The point is, yes his grease flew out. And dirt got in. But his CV joints aren't being used, they are just free spinning around all day not moving any torque. So yes his torn cv boot didn't give him trouble in a Toyota 4x4. It wouldn't have given him trouble in a dodge 4x4 either..
Yours will not/did not click or grind because it is not being used. You owned effectively a rear wheel drive truck with a switch/lever to make it 4x4. 99.9% of the time those trucks are in RWD mode, which means your cv shaft is not being used. It just free spins at most, transmitting no torque.
How long can it last like that? Basically forever.
I should add that I live in an area where ~40% of my driving is not on pavement, I am in 4wd at least half of my driving time and I have a second set of wheels w studs that I run from Nov to early Apr.