None of what you mentioned is really a wear part, except maybe the glow plug harness... But that's easy enough to make to your liking better than factory. Kind of like battery cables, some buy the off the shelf parts but for maginally more you can make your own just right and with larger cable. I don't wear out very many pulleys...
Mine is my daily driver and I don't feel nickeled and dimed to death. Yeah it sucked when I went from a 30 yr old truck I had been driving for years and just plain worked to a 30 yr old truck that was new to me. One I knew just plain worked every time no matter what, the other was a big unknown and gave me trouble frmo time to time. Someone mentioned it's better than payments. What are payments on a new econobox or a $50k truck to do what your IDI does? A lot more than monthly parts for even the most run down abused truck. Think about it, these trucks are now ~30 years old. If the previous owner didn't do repairs immediately using quality parts and take the extra time to do it nice (knock rust off, paint, lubricate, proper wiring, etc.) then yeah it'll suck for a bit every time you gotta do something but after a while you get caught up on all the neglect, things are done right, and you're good for another 30+ years without surprises. It doesn't last 3-5-7 or however long those suckers take loans for these days on new stuff, and by then the expensive repairs start coming up.
Sometimes things come all at once, like when I did bearings and brakes on both axles of my trailer that hadn't been done since new 25 years ago. Then the 460 truck needed bearings at 300xxx miles and the rear brakes done with entailing Sterling BS, then the diesel truck needs brakes all around... All I do is bearings and brakes! Got done batteries/cables/starter/alternator in the boat last spring, did the 460 truck not long before that, then the IDI needed batteries/cables/alternator, then the woman's battery died, and our bikes needed batteries in spring too... Right when I got done saying all I do is bearings and brakes it feels like all I do in batteries and wiring! Eventually you run out of bearings and batteries that need replacing though. Beats car payments and making bankers rich on interest buying **** I can't afford though, and when new stuff breaks it's not a quick cheap fix like these older trucks.
Think about it, they made this same basic truck for 17 years and a lot carried over from previous years and into later years. Wear item replacements aren't going away anytime soon. If they don't make it mass market it's because you can find good used or you can make it yourself. Hard parts are still plentiful for most things. Heck you can even get a new OEM quality dash pad, yeah $600 but that's what, one new truck payment? You got me on the rad support, but really you can patch a rusted one up or find a better one to do minor patching on. Eventually they may make one. No matter how you slice it these old trucks are absolutely cheaper, more reliable, and better all around than new disposable junk. IMO the '80-'97 trucks are the last of the real trucks Ford made. Maintain it and it will last forever. Once you're in the "I'll never buy another truck" mindset, you don't worry about that stuff... You just drive it and fix whatever needs fixing when it needs it, you'll always find what you need because they made so many of them for so long.