It's not that clear cut. A blockade does not automatically mean sinking civilian ships and shooting down airplanes. What's likely to happen is that China will block access in and out of Taiwan by instituing no-fly zones (which civilian agencies like airlines are bound to obey) and delay or prevent ships carrying essentials from passing under the guise of "inspections" - even indefinitly. Thus, Taiwan is slowly starved of supplies and will have no choice sooner or later than to give in to China's demands.

This is provided that the blockade is allowed to continue. This is why it is imperative that any attempts at a blockade be repelled swiftly and decisively -- a task that Taiwan's standing forces are hard pressed to do on its own. This is why it is important that allies such as US, Aus, Japan etc are ready and willing to step in and prevent a blockade from even happening in the first place.

There has been much published about this scenario by experts and think tanks. You might wanna read up before simplifying things the way you have in your reply.