Taiwanese Defense forces would not be “useless”, as a cross-strait invasion would be the most risky and difficult amphibious venture ever taken. Taiwan is working on improving their defense capabilities, and they’ve definitely fallen behind China, but the island nation has some chance of a successful (initial) defense.

I think D day would have something to say about the “most riskiest and difficult amphibious venture ever taken.

This is right up there; with significantly higher difficulty. For one, Taiwan has radar.

D-day in Normandy was a much shorter and more protected crossing than the Taiwan strait. Additionally, the Taiwanese are much better fortified than the Axis were, and they have radar along with anti-ship missiles.

So far, though the attempted Mongol invasions of Japan, while premodern, were on a similar level of difficulty.

The sea between Taiwan and mainland China is really a formidable obstacle to such operations, even without radar, advanced missiles and drones. Ships are expensive, slow and vulnerable; even the Russians had to yield in the Black Sea after suffering serious losses against a nation with no navy.

I don't know why HN has this wild idea that a potential WW3 costing millions of lives would be any way altered because TSMC is ~3-4 years ahead of Samsung/Intel. Entire world would lag by years if not decade if US defends Taiwan in case of full on attack.