Apple alone has something like 50% of TSMC's 5nm output, Intel has a significant portion as well, then pile in Nvidia, AMD, and the numerous amounts of Chinese companies who have their own GPUs being launched next year on TSMC 5nm, TSMC's 5nm is far more constrained than their 7nm is regardless of them not moving their CPU's over. Yes TSMC is ramping up their 5nm with an expected completion date of 2025 on the Arizona and Germany facilities. The transition over to MCM is not the golden bullet you think it is, MCM simplifies things and allows for easier to build designs with fewer failures, that's great, but you still need silicon to print them on and that is where AMD is going to be hurting for supply.
AMD has settled very comfortably into a position of a boutique hardware designer, they make limited-run, high-performance parts, at a maximum margin. It's a good thing for them, they will be making more parts than ever but don't expect them to be overly present in retail channels.
We obviously see the situation from two different perspectives. 5nm capacity will continue to grow, it's the current leading node at TSMC and has capacity coming online regularly, not just in 4 years.
Again, look at cpu availability and pricing. MSRP and available at any retailer. That's the power of having an 80 mm2 die vs the 519 mm2 Navi die. That's over 6 zen dies for each 6900/6800 and then toss in whatever yield issues there might be.
That advantage, being able to pick and choose which process is right for each component, will have a definite effect.
Hell, you don't even need to have each component made at the same fab. Cores on 5nm, cache on 7nm or Samsung 8nm, IO die with the same options, or even GF/Samsung 14nm.
The availability and performance of Zen 3 should really give a big clue to how this will all play out, even with all those different skus on 7nm, cpu availability only blipped last year vs console and GPUs.
Small die size to enable maximum # of parts per wafer with low reject rate and fab agility for components will have a positive effect on GPU and CPU production.
Whether that will be enough for consumer demand and crypto........¯\_(ツ)_/¯