Taiwan Semiconductor Manufacturing Company (TSMC) was founded in late 80s and introduced a completely different model to the market of semiconductor manufacturers, which were all focused to both design and manufacturing of their own chips at the time, Intel being a prime example of that model and the dominant player then.
What TSMC did was to focus exclusively on manufacturing chips under other brands, and they became better and better at it. Since they didn't handle the design of chips, only the R&D and production of chips, they started carving out a larger global market share of the semiconductor industry as time passed, and the manufacturers with integrated processes had a hard time keeping up the pace.
Currently, they have 50% of the global semiconductor manufacturing market share, and one of the only top-notch R&D labs for chips.
Samsung is struggling to keep up on R&D, Intel wants to revive R&D but they are way behind, most everyone else relies on TSMC for creating their super-performant chips. You can count here Apple, Nvidia, AMD, etc.
Grok says a single advanced fab costs upward from $20bn, and TSMC supports these costs on its own, which is another competitive advantage to attract smaller customers and to bolster innovation from startups.
One can say it was and is a matter of national security for the United States what happens with TSMC, given its new rivalry with China, and the latter's claim on Taiwan.
It is quite possible that even Uncle Sam won't be able to protect Taiwan from China's claims for much longer, that's why the deal they reached in Trump's first term was "upgraded" after a little public arm-twisting during his campaign: "Taiwan should pay us for defense", which probably was put into practice when he became president.
So, on Monday, Trump & TSMC announced a $100bn deal which would build TSMC production in Arizona. Trump said that after this, the US will have 40% of the global market share in semiconductor manufacturing. Great deal for them! May be a good deal for TSMC too, which won't be as centralized. However, from what I heard from experts in the technology field (way before this deal was announced), it will be hard to find workers anywhere else in the world that have the same competence, work ethics, and are as cheap as they have over there (compared to their qualifications). We have to assume chips produced elsewhere than Taiwan may be more expensive for this reason. Unless they export the workforce too?
I don't think this is good news for Taiwan. Once the US becomes a force in semiconductor manufacturing, it could back down from protecting Taiwan from China.
Maybe the fact that R&D will likely remain in Taiwan will make it something to fight over, given how few competitive R&D labs for chips are in the world, and that they are the best.
The deal also infuriated China, along with the additional tariffs. I doubt they will watch and do nothing, but they are not the kind that rush into things.