It feels like this is something you should get by being owner of the car, and not have to do free speculative research for the manufacturer to get it.
Right-to-repair legislation is chipping away at this but slowly. The EU's right-to-repair directive covers physical repair and doesn't really touch software access. The real test would be a regulator taking the position that restricting root access on hardware you own constitutes an anticompetitive tying arrangement, since you can't use the car's data for your own purposes without going through Tesla's APIs and paying their fees.
John Deere has been the main battleground for this argument so far. Farmers can't repair their own tractors without paying for dealer access to diagnostic software. Tesla is the same pattern applied to consumer vehicles, but the consumer advocacy pressure is weaker because fewer people feel the pain directly.
No i'd push back on this because the entire workshop manual is available for free without even registration required. You can literally google and land in the relevant sections and it is of a far higher quality than ford, VAG or bmw as three examples i'm pretty familiar with. I haven't seen the John Deere stuff.
Tesla does have "special tools" for some repair procedures, a practice as old as the auto industry but they don't rely on them to the same extent as BMW for example. Anecdotally, the special tools i'm aware of are genuinely useful - for example, the tool for disconnecting seatbelt anchors saves time vs the traditional bolt - where special tools on other marques are often clearly to workaround a failure of packaging or engineering resulting in tight access for a regular tool.
Their online API access is a little bit annoying, or at least unfriendly to casual home user, specifically the workflow to register an OIDC client, but not insurmountable.
It really isn't. Unlike John Deere, Tesla is actually pretty good on right-to-repair. All of their technical and repair manuals are available for free to anyone. The service/diagnostics software ("Toolbox") is also available to anyone, albeit for a (not entirely unreasonable) fee.
(There is also a service mode built in to the car which can do many basic diagnostics for free)
How is this different from the 2000s, or the 90s, or even before, when the normal thing to do with commercial software was to purchase a license to use said software and a physical medium containing a copy? You'd also then not "own the software", but you owned the right to install a copy on your own computer and use it. That worked without having to hand over the keys to your own computer.
Sure, the physical delivery medium is gone, but that's just a detail. Why do we now think that just because we license software for use, we can't be in ultimate charge of our own devices?
As a pedestrian I prefer for most people to not have root access to their multi-ton fast-moving killing machine.
This is about selling tools and access. It's another profit pipeline for car OEMs.
Almost invariably when that excuse is trotted out, there are are usually many things that are much more common that are also far more dangerous. For example, texting while driving or driving with bald tires in the wet are both 100x more dangerous than anything almost anybody would do by modifying the car's software.
Manufacturers have increasingly restricted control over products as they've gradually been digitized. Prior to the digital era anyone could do anything to personal property (regulations notwithstanding ofc); more expensive items typically came with circuit diagrams for the purpose of repairing them.