Earlier Jeeps were made with earlier technology that is more rugged. It may need repairs and parts replaced, but the parts were fairly inexpensive and easy to replace, the major items, like axles/differentials, driveshafts and engines lasted forever, although NOT that efficient.
The newer Jeeps that are based on FWD car platforms, FWD layouts are NOT known for longevity. They typically tear up the transverse drivetrain well enough by high miles they are just NOT economically practical to repair. Of course there are always exceptions, I'm sure there are some high-end FWD that last very well, and more than a few driving a 250k mile Honda civic bragging about it despite it clunking and shaking and making all sorts of noise while it drives.
To get at what rubicontrail eluded to, the more modern Jeeps that still have the same layout of the old Jeeps, the Wrangler, Grand Cherokee and our Commanders. They have more modern technology in them and thus subjected to modern difficulties, so its tough to predict.
A few things on the Commander/Grand Cherokee you didn't see on the old Jeeps that are the same layout; Non-Replaceable U-Joints, the entire driveshaft has to be replaced. Front Shocks that are Coil Over Shock with HD Mount like a Strut, making replacement more expensive, difficult and longer. Electrical Shifted Transfer Cases, again increasing cost of repair and replacement, etc, etc.
So arguably, you hit that point of repair and maintenance becoming more than is economically practical way before you did some of the older Jeeps that could be fixed up rather inexpensively and easily.
There are still 4th hand Jeep Wranglers and Cherokees from the 80's and 90's, being fixed up, modified and used as pure Off-Road beater/hobby vehicles. Arguably, you may see very few 2005 and on WK/XK vehicles being used for that. The cost and/or difficulty to fix them up may be just impractical for a hobby rig.
Oh, and to be honest, if you were to look close at some of those beater rigs run awful and have worn out motors that should be replaced. They really do keep them running on bailing wire and spit. And that is also a problem with the regulations and standards for new vehicles, they have so much technology and emissions monitoring, you can't keep the motor running, there is no room to improvise, no compromises, no tricks or work around, fix it right or it won't run. Meanwhile motors from the 80's, my belch black smoke and blue smoke, but you can rig it to keep running.
Oh BTW, I have 138k miles on my 2010. But I have NOT done a lot of off-roading or stressful driving on it. Only thing I consider a "black mark" on quality/reliability, the AC evaporator failed around 60k miles, recurring a very expensive repair. The rest I had a TPMS sensor go bad, EVAP/Purge light for a bad gas cap, a bad Engine Coolant Temp sensor, all I consider well within normal wear & tear, maintenance and reasonable repair of owning a vehicle.
I replace shocks and strut mounts at 110k miles (a little later than I should have), again normal maintenance.
I currently have some misfire codes (even with new plugs) and rough running on cold mornings with a cold engine. I think it may be a bad PCV valve or EGR behind it, at 138k miles, I consider that well within reasonable maintenance and repair, as part of owning a vehicle.