Apple does indeed provide years of OS support for every Mac they sell, at least five years but often much longer. And whether Apple has 1, 3, 5, 10 or 20% of the market isn’t particularly relevant. The point still remains that Apple doesn’t have a monopoly. There’s no such thing as “monopoly relating to a product cycle” and Apple is under no obligation to use any COTS parts unless they so choose.
Sounds like Apple history about to be repeated.