I actually work in the industrial repair industry. The thing to remember is not every company is insanely rich. Maybe top level companies but they are supported by a wide network of smaller companies. Those smaller companies don't have a ton of money to throw around. The manufacturers of the equipment have become quite greedy. The majority of them offer whole systems and then if anything breaks they want to charge an insane amount to send out a field engineer. And then if something is broke most of the time they either don't carry that part/panel/whatever in stock and will try and upsell you to the new model which is of course a massive investment.
So repair shops fill the gap for all these smaller companies and factories to get support higher than the on staff maintenance. Not everything is fixable though. They may use unique hardware signatures on drives or FPGA's or PAL's with security bit enabled. That has been true for a while though. Even in consolidation there is still plenty of business and repairs to be made.
Conversely the medically industry might be a good example. Anyone making medical equipment has to provide documentation on it. Which makes them far more repairable and easily diagnosable.
TV's especially are peak commodity. They are so cheap that the skilled labor cost to fix them isn't economically. They also are not easily transportable so repair and resell is a rough business for them. Things like laptops and phones though seems much more reasonable. Plenty of people do that professionally or even as a hobby. I like a large portion of repairs on those types of devices can be fairly economical and Chinese part makers provide plenty of affordable parts. It would cost OEM's extra to keep these parts in stock, but it's not a terrible hard task. Providing schematics also isn't a huge ask. Most are reverse engineered anyway.
When it comes to security I think this is fairly simple. Provide a blank security chip and create a secure method to connect and program it. Apple does this with its self repair when it comes to matching hardware UID's in the firmware so all the functionality is unlocked. Companies like Apple and Samsung can keep their Knox and Secure Enclave/exclave. Data can be seen as something that is not repairable in most cases. But they can provide the parts the secure a device again and leave it as a blank slate.
The biggest problem with Right to Repair is pricing. Right now Chinese makers can whip out parts for really cheap. Comparing to official parts from Apple or Google or Samsung when they did sell them and they are way higher and sometimes prohibitively so. Would be better to treat it like auto parts. Where you can get the OEM part or the third party part and both can work. Some things like security would need to be first party, but that would be a great deal. So it's doable, but would require a LOT of political will against tech companies. So it's just a really tough sell to get to that point.