> Consider the availability of schematics for MacBooks, for example. They are not available officially. But it is possible to get them via shady channels. The operation of such channels is risky because it is often illegal. But it is nevertheless being done because there is a large demand for it.
If you buy a BMW, you drive all around town and get told by auto places, "Hey I don't work on BMWs." You end up taking it to a dealer, or an approved repair place. I don't see why a phone or tractor or anything else should be different.
If you want something that's got modular parts / open schematics... make that a consideration when buying. It comes off as, "We want a premium product, but we don't want to pay a premium repair price or use approved parts... rather just sort of have it be an Apple case with Bubba's MacBook Repair & Tackle Shop approved parts... and Bubba can warranty the labor." Oof.
Apple is pretty up front with their products, if you buy an Apple product odds are if it ever needs to be serviced you'll have to take it to an Apple Store. AND... the kicker... they have great service.
A schematic isn't enough. Like you'd have to provide order of operations for disassembly (at least some training), odds are tolerances for glue / tape removal, etc. Doesn't seem unreasonable for Apple to say, "Hey we make a premium product, and we're the only ones with expertise in the care of that product. If you don't want an Apple laptop, you're free to buy Bubba's DIY Laptop built with 100% Organic Duct Tape!" And plenty of PCs went that route in the 90s / 00s. Open architecture was a selling point.