> must be forced to make parts and schematics available to any independent repair shop, just like car makers have to do

The only reason this has been possible for car makers until now is because the technology to stop it didn’t exist. But it does now, and car makers are definitely moving in the direction of “lock down”. You already can’t replace wireless key fobs, and entertainment head units are locked down. Repair manuals are locked behind a monthly subscription web site, and the third-parties who used to publish their manuals are giving up. John Deere is infamous for taking it to the next level with farm equipment. The way things are going in the auto industry, as soon as it’s possible to technically enforce the use of “genuine” crank shafts and head gaskets, they will not hesitate to do so.