That's like super naive.
First, you mentioned it. "It has sure been profitable". That's kinda the whole point. You get more profits, you use those profits for R&D to further distance yourself from the competition.
If there is any way to reduce your risk it is building a technological edge over competition and sizeable cash reserves.
Second, even if Apple faced complete stoppage in production, its situation is different from other companies. It not only can do things that other companies can't (like pull cash to build entire supply chain in some other place), it also has devout user base that will mostly just wait for Apple to come back. People who buy say Samsung laptops and phones will switch to another brand with no second thought if they can't buy Samsung, while people who buy Apple will try as much to wait and will not switch easily.
Third, the US is currently the guarantor of Taiwan's safety so maybe the risk isn't as big as you think.
Fourth, if TSMC is unavailable they will spin the production somewhere else. And who do you think will get the first chips out of it -- the companies that are the most ready (Apple, they already have all the know how and designs), the companies that are ready to pay the most for the privilege (Apple, because of their cushy margins) and the companies that have the most weight behind them (again Apple).
So no, I think that saying Apple's risk is obscene is just naive. Apple has positioned itself to be best at weathering any storm that might happen, it knows the competition will be hit even more and is using this to reap as much benefits as it can while the party lasts.