1. China is no longer so weak or unconnected that PLAN expansion serves to protect its sovereignty from Western intrusion. It would be utterly bonkers for the West to launch a preëmptive or unprovoked attack on China. There is no credible risk of a recurrence of a century of humiliation that is being prevented by the current naval buildup.
2. Current PLAN expansion is useful on a scale of decades rather than centuries. It is doubtful that the same ships will be helpful in two or five hundred years.
3. PLAN expansion is part of a broader more hawkish strategy (also in Hong Kong) that makes much more sense on the scale of decades rather than centuries. Taiwan was on a very slow path to HKSAR-like status in the 90s, and both HK and Taiwanese separatism are fundamentally reactionary phenomena that would not have gained significant traction but for fears of an /illiberal/ China. Peaceful economic integration and close people-to-people ties would have been far more effective on the scale of centuries—the problem is that one has to wait.
4. The strategic advantage PLAN expansion confers is plausibly time-limited. The PLAN is building ships far faster than everybody /right now/. That advantage may well diminish soon, depending on US/Aukus/Japanese politics.
5. Demographic factors (on the scale of decades) will soon pose a problem.
Given this combination of factors, there is a period in the next decade or two that will plausibly mark the best opportunity for decisive action to take Taiwan for perhaps the next century, and the zhongnanhai clearly wants to make the most of it. It doesn’t follow that invasion is guaranteed, but it seems a fairly safe inference that the zhongnanhai wants invasion on the table.