Why would they? With the current arrangement they get all the benefits and none of the risk. If TSMC falters they can go to whoever supplants TSMC and make the same arrangement and continue to have the latest and greatest chips.
They could annihilate all competition in the market except for them. Every single Android phone would be forced to use subpar manufacturing from there on out.
Why do you think the US or EU would get involved?
Isn't that kind of how it is already?
All this would do would weaken TSMC and strengthen other chip manufacturers for a couple years of absolute chip dominance. But they already have chip dominance, so it is for essentially zero gain.
They become part of apple. With a stranglehold on chips the price of apple products as a whole, or their sales, will skyrocket.
Besides buying a major supplier out and then getting rid of their other customers is value destructive.