Yeah probably an actual military move on the land would be too much and reckless considering many aspects. 

I never heard about those points of Taiwanese birth rate and migration, very interesting.

I do agree with you for the waiting of US decline and in this particular sense I saw a more aggressive move in Taiwan, and I mean about influence and or supply and markets control.

What I see is some move made by China in the chess board, and this could mean a small one now in order to speed up later.

But ofc I am just speculating and making scenarios in may head.. sometimes those come true.