That's because they were forced by Massachusetts expansion of Right to Repair laws. Before that in 2021, service manuals were withheld and required $3,187 a year or $371.88 a month to see them. Before that in 2018, it was $100/day to view them. Before that, you had to pay and book an appointment and go in person to view them.
Craig's point about the special tools being well-designed is fair, I don't think Tesla is uniquely bad on the mechanical side. but the software lockdown is a separate thing from workshop manuals. you still can't get root on the infotainment system or run your own diagnostics without going through their API, which is the part that's more like John Deere than a traditional automaker.
Here in the UK (where i also have free tesla repair manual access) i have to pay a daily rate (there are annual subscriptions available) for other marques and i would say it's not cheap.
For example, ford charges me £20/hour or £75/day for access to manuals, wiring diagrams, online connected diagnostics (which sounds more impressive than it is, the UI will show vehicle status like fuel tank level or error codes reported by the various ECUs, without physically connecting to the vehicle, i.e. it's done over the vehicle telemetry link), and the ability to connect via a data link connector device for diagnostics and some reflashing activities. Security activities like key coding require a further (chargeable) registration).
The same setup is available by at least VAG, BMW and Fiat Chrysler (the latter has an annoying extra device registration step the others don't). All chargeable.
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.