That's because apple bought the entire 5nm production capacity/runs for basically for the entire last quarter of 2020.
I can tell you some companies were not too pleased about that.
Ah yeah, Apple has f-you money and it knows how to use it.
They did this with FedEx planes out of China years back, forget which iPhone version, but they basically did the same thing they booked everything. All FedEx planes only had iPhones and everybody complained. I don't think they have tried that stunt again.
Is there anything preventing those companies from "ganging" up on Apple and buying capacity jointly? Are they too many and too small? Is it possible to share wafer-space with other companies or does having multiple designs add too much complexity/cost?
I think Apple essentially outbid them, which it was able to do because it is has both large volume and large profit margins.