Apple can come to a vendor and say "these are our constraints on what we are willing to buy. Here's testing benchmarks. You are required to meet them. Failure to do so voids the purchase contract."
The vendor will then, of course, say "We'll have to charge you more if we're spinning up a test infrastructure we don't have."
And then Apple will negotiate a price point and pass the anti-savings onto the consumer.
They do this at multiple levels at multiple points in their hardware story. I met someone once who worked on the USB integration specs back in the first-couple-generation iBooks. Apple built a rig for physically testing the connectors (including multiple cycles of intentional mis-plug, i.e. flipping a USB-A connector over wrong-side-up and pushing hard against the socket). They told the vendors selling them USB sockets that the sockets had to survive the rig, or the sale was void. Vendors priced accordingly. But the resulting product is more robust than others on the market.
I'm not sure about this. There are people who pay >1000€ for their flagship phones and believe them to be premium products, but they are just as buggy as the cheap ones. Huge amount of CPU power and impressive camera specs, though.
The S21 Ultra seems like a very good purchase from reviews. QHD screen with dynamically adjusted 120Hz seems really like the best spec.
Apple sounds like it really is that rigorous with the quality of hardware and drivers/firmware they use.
Some of the stories of nitpicking that I’ve heard are truly awe inspiring. On the other hand, I’d hate to be the engineer on the vendor side trying to please apple. (Mostly because some crap PM or sales person made promises without consulting engineering on what’s possible with the available time and resources)
We've been together 4 years, its USB port is a little loose now. Too much charging everyday, but the screen is still pristine. The camera is fine so we can go out and take photos at the beach. I'm happy man. It does what it said it would do and did it. And still doing it.