Using the same theory that the tool is only $100, why do all the quality aftermarket tools cost thousand of dollars? Because it isn't just the tool, it is all the R&D it takes to make it work. If it was so easy and inexpensive the aftermarket would not charge what they do.
Look, they develop all that when they BUILD the VEHICLE (actually, one software development covers many different models of vehicles from the OEM). When I BUY said vehicle, a portion of the purchase price has PAID for that software, because it EXISTS BEFORE that car rolls out of assembly. You are not going to convince me it's not a rip off, it is, and I should point out, outside the US tools are much, much cheaper, as are Rx drugs, for similar reasons... The companies have figured out that the US market is willing to grossly overpay for things... and they price accordingly. As to the aftermarket, they have to PAY for the access and rights to use the same software code the OEMs develop, and since the OEMs would prefer to sell it themselves at their ridiculous prices, they don't offer it cheap to the aftermarket, which in turn passes the cost to the consumer… It's really not complicated, but keep in mind, GM, FCA and many other OEMs are selling cars outside the US that run the same software, and overseas access to affordable tool options are available, and likely in part due to the laws in other places..
As I have said over and over, I have no issue with reasonable cost to access the technical information systems, and I'd be happy to pay double the cost of the import stuff, if that were that price.. but $3-$4 THOUSAND dollars for a tool that uses software that is 11 years old, or older.. It is just not reasonable... It just is not and there is not why you can show the math on the COST for this old software that justifies those prices... It is pure rip off massive profit that is in play.
I get it, OEMs are having serious problems with a working business model to make vehicles and obtain a profit. CAFE standards and other regulations and requirements drive up the cost, and they either make high MPG vehicles the people are not buying, at a LOSS, or they pay fines or offsets to Tesla or another car maker that has exceeded its CAFE standards.. This drives up the costs dramatically.. That said it's not a good play to expect people to pay such insane costs on tools, the shops that work on many vehicles and make it work by volume, but not the owner, and I find that to not be a coincidence... ultimately they don't want to offer any access as you noted is a problem with Tesla.. There has also been issues with big modern farm tractors as well, the delays to get a technician and costs are huge for farms, where they could likely do many service items themselves if they had a working computer tool.. You can do some looking up on that issue if you want, and it has led to a market of tools coming from overseas, because there is a demand created there by the OEMs not being reasonable with the customer in the first place.
They should price the car when sold to account for the cost of development of the software and tools used to service that vehicle. Expecting to charge thousands of dollars, and ALSO having expensive subscriptions to access updates for these vehicles is not reasonable when taken together, and hence there have been laws forcing them to make provisions for independent shops and the aftermarket. As I pointed out with my Land Rover, there is a reasonably priced comprehensive computer tool I purchased for it, that is VIN locked, so I can only use it on just that one car, but that keeps the cost reasonable. I can find no such options for US OEMs anywhere (closest thing was AutoEnginuity, which I did buy).. and when I looked recently, I stubled upon what I thought was the VCA OEM tool wiTECH (in everything I read online said it was, and it does have all the markings and functionality, as far as I can tell it is the OEM tool).