They'll run out of something necessary eventually - food, fossil fuels, ammo, etc - forcing the US and allies to decide whether to intervene or not.

I hope the US is ready to go with orbital kinetic energy weapons. Ten thousand or so projectiles, each made of 50 kilograms of tungsten, raining down at multiple kilometers per second, would likely...suppress...any attempted blockade.

"Star wars" is feasible with reusable launch to orbit vehicles.

Just like we did with Ukraine?

Ukraine wasn't blockaded.

Taiwan does have fairly good stocks of weapons and ammo. It's also great terrain for fighting a defensive guerilla war. It'd be China's roleplay of "Russia in Afghanistan".

You’re missing the point, which is that we very much did not arm Ukraine ahead of time, just like we are not arming Taiwan right now in required volumes. China could literally blockade Taiwan tomorrow, and our arms are simply not there. What you propose depends very much on getting enough intelligence to ship all the arms they need before the blockade actually starts, and China not blockading Taiwan as soon as it learns about shipments leaving our ports.