Taiwan is a small island, it lacks lot of basic natural resources, like oil, iron ore, etc. One simple thing that China could do is to send their navy to cut off all the supply lines: it won't take long before Taiwan is degraded to third world country. Without the US navy to counter Chinese they do not stand a chance.

You're talking about it being hard to resupply Chinese troops over the air, how about resupplying the whole Taiwanese population?