Why invade when a blockade would be more effective and cheaper?
Blockade takes too long.
Also, if they take Taiwan, the Chinese will be in control of 80%+ of the world’s first line semiconductor production between what they own, what’s already in China and Taiwan’s resources. Look at who TSMC makes chips for, for example.
Most of the rest of the world has much older, far less capable foundries that aren’t capable of producing the current standard 7nm chips.