I don't, I just work in the industry. These aren't an either-or decision on Apple or not Apple products. IP from developments on Apple-exclusive stuff is used elsewhere. Look at TI's USB-C port controllers as an example used in Macbooks. They have a custom one for Apple, but you can buy their general market parts online just fine. It's not like Apple is preventing TI from selling USB-C controllers.
> OK. I'll take you up on that guarantee. Feel free to reply with reputable sources on the matter.
You won't find 'published sources' on this. You'd need to have a fundamental understanding of semiconductor industry. Support for general market customers is HARD. They tend to be particularly needy, especially compared to the return on investment. If your organization is designed around helping large customers (not just Apple, but any large customer) then you just do not have the appropriate business structure in terms of sales, distribution, etc, to manage that. Companies like TI/NXP/ST have that infrastructure, but there's plenty of smaller companies that just do not really support small customers.
I get that repair shops 'just want to buy the chip', but that's really not what making parts available on the market means. It means fielding questions, publishing datasheets, having FAE/sales support, having distribution channels, etc, which all adds to cost for very little ROI. Repair shops are basically a rounding error in terms of buying power compared to a Samsung, Apple, etc.