Not really over the top. The issue is not the computer, the issue is the OEM trying to lock you out of the computer you purchased.
I had an old Jeep that would read out trouble codes in the dash. 2002. There is no reason they can't do it in their fancy touch screens today. They simply choose not to. So its neither a computer nor a tool issue - its an OEM issue.
OBD1 wasn't really a thing. There was no standard, everyone did whatever they wanted. Hence OBD2.
I agree, I really don't need a CAN controller in the tail light, or my radio on CAN to talk to my ECU. Again, thats an OEM implementation issue - not a computer issue. They could make a networked system that was easy for DIY people to use and troubleshoot - they choose not to. Some OEM's are better than others. For example Toyota gives you an algorithm to see the proper transmission temperature for refill with no tools. Nissan still does "Active Auto" test which basically cylces through everything electrical so you can see if its working - lights, wipers, horn, electric fan, etc.
Ford and GM lock you out of everything is my understanding.