sure, most of them are replaceable, but It is about maintaining ties, to make them keep dependency on China.

if we cut them off now, they will learn how to live without Chinese market

just like how China is learning how to live without US chips now

they may not be able to find another market like China, but there are plenty of substitutes that are good enough, after all Taiwan isn't a big country with a big population, it is even greying faster than China, more importantly, China has become a competitor to them too

ever wonder why the South Koreans today turning hostile to China? It is not just because of THAAD issue. It is because China has become a formidable competitor to South Korean industry. South Korean industry not just risk losing Chinese market to Chinese competitors, but also risk losing global market to Chinese competitors. That's why they don't feel they are losing much in challenging China now since Chinese competitors are coming for them anyway. I bet they are even happier that the US is currently launching a trade war and tech war against China, just like how Samsung benefitted from the demise of Huawei phone business.

with less ties, that is what happen. Friends/ clients turn into stranger even enemy. In Taiwan case, it is even more so since there is reunification issue. Unless China want to take Taiwan by force, then yeah it is okay if you want to forget about building ties since China is going to pounce them anyway.

btw what happen with South Korea today, is probably happening to EU soon. As we can see, EU feel threatened by Chinese EV, and they begin to provoking China politically since there is less cost to do that. I wonder how long before they start meeting dolly lama again. They have been flying to taipei more and more often. Clearly the EU feel the Chinese carrots are getting smaller and the sticks are getting bigger. This isn't good for long term relationship.