You know, a newer thing that gets lots of remarks like that is the Security Gateway Module (SGM) from FCA (Chrysler) on 2018+ models. Everybody thinks its getting locked away from end users except read access. Less understood is along with this change they now they sell their micropods for $1800. (obd2 wifi dongle) Meaning, for under 2k you literally have the same tool the dealers have to use. And you can pay for 3 day subscriptions for $50 a pop that give you access to everything (firmware updates, repair procedures, wiring diagrams, etc)
But if you still want to use a 3rd party tool you pay $100 a year for an autoauth subscription that supports all tools an independent shop could possible have among all their employees. That effectively allows the 3rd party tools to request FCA unlock the SGM so they can program the car directly with aftermarket tools. And if you just don't want to deal with chrysler or care if nefarious actors can potentially hijack and program your car over a cellular connection. You can replace the SGM with a bypass and even ditch the cellular connection. Or you can add another OBD port for yourself by plugging in at the star port. Or use something like the 8+12 method.
So its not like John Deer or Tesla where you can't do anything. Its more like if you owned an Apple computer and Apple allowed you to purchase their software to work with it. And did so at a very reasonable price (comparatively) any independent shop could afford. But also allowed you to register with a auth service that allows you to disable all the stuff blocking you from doing things with 3rd party software.
If we're going to go down this road of cellular vehicles I really hope FCA being out there ahead of others rubs off on how other manufacturers handle it. I think its a pretty good engineering design to address modern concerns as well as support independent shops by extending access to their tools to work with. You don't have to worry if Autel or Snap-On understood something well enough to program the various modules correctly. But you can still go that route if desired.