There's now AMD laptops certified for Thunderbolt 4 coming to the market, such as the Lenovo ThinkPad T14s Gen 6 [1], so it's no longer this clear cut.
I recently needed to buy a raspberry for my hobby project and find one close to retail price via [1] which tracks availability across different online stores.
This development of market dynamics & structure has been famously featured in the book "Only the Paranoid Survive" by Andy Grove, which I can only recommend (it's a quick and easy read).
Anecdotally, it seems to me that today, the more successful companies are those that tend to be vertically integrated, such as Apple, Tesla, and Amazon.