They pay TSMC loads of money to have the first chips for each process node. They were first to 5nm, they'll be first to 3nm next year too. This is because they sell whole products rather than chips like Intel and AMD, so Apple's profit margins are astronomical compared to them, and so they can afford to pay TSMC so much.

Oh I didn't know that, thanks. So it's more that they bought out all of TSMC's product, rather than that they came up with an innovative new process.

Well, they bankrolled TSMC's R&D for N3 nm and N5, which allowed TSMC to increase capacity and get to new node ahead of competition.

Well, they also have some of the best silicon engineers in the Valley, and the world. It's not just TSMC, they only build what is designed.

Also their products include iPhones and iPads. Intel nor AMD are putting their chips into 10s of millions of phones, especially phones people will pay top dollar for, per quarter.

They bought out TSMC fab capacity by biddng significantly over AMD.