Imagine the states like Pa, where they have the state inspection, and many places the emissions test. The city I lived in, you cannot even have a non inspected vehicle on your property, unless it was in a garage. I ended up scrapping my 86 RC, because of all the rust on the underside, exhaust system, and worn out spring and shackle bushings. You take it in for inspection, and if it does not pass, they can remove the good sticker, even if it has not expired yet. Then you cannot drive it home. Back then, you could not get the spring bushings anywhere. So it was new springs all around, The tail pipe, and crossover had pinhole leaks, And the rust was at the rear body frame, into the corners where the hatchback closes. It looked fine until they poked it with a screwdriver. It was all much more then I could afford, and I had no place to legally park it, so I ended up taking it to the scrapper. Made me sick, but at that time, I had no choice.
Many years prior, I almost did the same to a Subaru. It just started smoking like crazy out the exhaust. I replaced the valve seals, and did the timing belt, and a bunch of other seals while I was there. It still smoked like crazy, I took it to two different Subaru dealers, they both said the engine needed rebuilt, which was out of my budget then. After getting two tickets for uninspected vehicle, I had time to really look at it. it was an 86 cent gasket for the turbo charger. Also had the oil port going through the gasket, and it was pumping oil right into the exhaust, at the turbo. I do not believe the dealers never had the gasket go bad like that.
Sorry, I wandered off track. Yes, it is going to get ugly with many parts. The booster will likely be among the first, as many are original, and just starting to go bad. With no known workaround right now. The you have the door latches, that never were made aftermarket, and many are wearing out, and having the plastic on the latch part start peeling off. Steering col parts. And ?
Whats next? heater core, AC evap, wiper motor, blower motor, heater control cables, Wiper & heater switches, To name a few I can think of right off.
I guess we should start making a list, and any known substitutes, or workarounds.
?? Don't sound right to me.
chevy p/u / 1 ton ? or a new( 2000's) international 1 1/2 ton , install that , or realize many disc brake autos years ago had NO booster , example ; 1966 Barracuda S, 4 piston discs , manual , and even manual quick ration steering box .... 1960 full size ford , no power nuthin , it did have a optional heater . 
