Sure, I'm not making any claims on whether they can successfully do that, just that in this widely-studied geopolitical contest, it's the most likely move that they will attempt to achieve their publicly-stated goals. (And not some crazy all-out war on the US and its allies as GP was proposing.)
FWIW on the likelihood of this specific claim, my impression is that the Pentagon considers it likely that they will try to annex Taiwan at some point in the next decade, e.g. see yesterday's headlines from Blinken (https://www.bloomberg.com/news/articles/2022-10-17/blinken-s...).
I don't have any particular domain knowledge to judge how hard it would be for China to occupy Taiwan (or how much more military power China would need to tip the balance in its favor), but I'm interested in any hard analysis that you can share on the subject. The general reading I've seen has suggested that they would be able to do so in the next 10-20 years if current trends in military growth pan out.
