I don't really understand why you say this. For example, gorilla glass is an illustration of exactly what I mean: Apple controlled the supply and drove corning to both change its formula and ramp up production unexpectedly for Apple. Apple happily paid for this. It was driven by Cook.
Likewise Apple buying up a huge percentage of milling machines for aluminium and sending them to their suppliers.
Apple's supply chain is multinational. They get heavily involved with vendors/suppliers, not simply Hon Hai and TSMC. They are willing to work with competitors (e.g. Samsung).
They have made the switch to USB Type C both in USB (they are on the USB committee and had a lot to do with the design of Type C even though they were also working on lightning) and Thunderbolt (which they cooperated with Intel on).
They are quite far from "independent"
I do not thing they've interoperated with other companies well at a high level. Thunderbolt was all due to jobs - he got intel to do it (andy grove?). It's now back in intel's court now.
Instead they bring more and more in house. Their hardware can't run windows anymore. Their software has gotten less and less flexible. They let other languages rot, it's obj c and swift. Their hardware has gone back to making g4 cube type mistakes. again. and again. Ask anyone about the ports or the keyboard on an apple laptop and you'll get an earful.
Just my opinion.
He was the great integrator. music, movies, chips, even the gorilla glass thing. Roped in all these people.
This is seven habits stuff: dependent -> independent -> interdependent
Steve Jobs got Apple into a big web of interdependencies where everyone moved forward. Had the whole valley involved.
Now Apple's regressed back to independent.