Exactly. Apple could build a fab and expend a few percent of their cache of cash.

If money's all that's needed to build a fab to match TSMC's 5 nm without prior experience then their biggest competitor would be China's SMIC. They have unlimited funding from the Chinese government because an embargo hurts China's electronics industry a lot more than just price gouging. SMIC, a company with unlimited funding to poach TSMC engineers and actual experience with chip fabrication is still 2 gens behind. Apple's not going to do any better.

I mean, it worked for chip design.

Apple's breakthrough came years after acquiring PA semi and Intrinsity -- and neither required $10B in annual CAPEX to maintain their lead in chip design.

I think Taiwanese engineers rather work for Apple in the USA than for the State owned companies in mainland China.

They have the money and can attract the talent

TSMC is already a major Apple partner, Apple had no reason to start a talent war here. Remember, Apple squeezes suppliers and labor (wage fixing from the Steve Jobs days).

They only build their own stuff when they see a competitive advantage to doing so — when IBM stopped delivering on chip efficiency or when Intel’s chips started stagnating.

TSMC is known to be very selective with cadres. People who are given "keys to the kingdom" are selected among all things upon loyalty. Take a look on their number of GMs, and VPs with 10+ years of work at TSMC. At the highest levels, TSMC kind of stops being a company, and starts looking like a fraternity.

You can't just create new fab with money.

There are other fabs in the world outside of Taiwan. It would be within the realm of possibility that Apple could purchase a company with good but not great fab capabilities and improve output with strategic hiring.

Like they did with an electric car?