> Donbas is mostly wheat fields

... which nevertheless are very important worldwide. Early in the war, there was a lot of effort to make sure grain exports could run smoothly because otherwise Africa would have been in serious trouble.

> The global response would not be the same, even remotely.

We're already at a stage where Trump doesn't give a single fuck about NATO and some of his advisors would rather have it disbanded yesterday in favor of isolationism, or even outright march into territory to annex it. I have absolutely zero faith that Trump would intervene on Taiwan's favor - an intervention does not fit into Trump's and especially Miller's world view wherein the world is to be divided into areas of influence for the super powers to act with impunity.

> And what would China get from it? A tiny island of rubble and an ego boost, while losing enormous global favor?

Never underestimate nationalist idiocy. Putin invaded Ukraine because of his dream to restore "Great Russia", it is entirely possible that the CCP wants the same for the ego of their leadership to be the ones "bringing the lost areas home". They already did so with Hongkong, and not reacting to China violating the treaty with the UK was the biggest mistake the Western nations have ever done.