It's not just building a product end-to-end. Tim Cook is a supply-chain guy. He knows how to build a product. What he doesn't know how is how to design a new one. This is the reason that all of the "new" stuff that has come out of Apple since Cook took over is actually just riffs on old degrees of freedom: thinner phones. New colors. Different UI skins. The only thing I can think of that Apple has done in the Cook era that was actually new was the Apple Vision Pro. That was really cool, but it was a commercial disaster, the modern equivalent of the Lisa or the NeXT.
Jobs took Lisa and NeXT failures and turned them into the Mac and OS/X. There is no hint that Apple intends to do anything with the Vision Pro, and they've already been scooped by Meta.