Agreed. I've been doing a lot of thinking about this over the years, and as far as I can tell, if it does happen, it will be the result of at least two or three essential elements coming together. In other words, I don't think it will happen, at least in the next 2-5 years, purely as a result of China wanting to take back Taiwan.
If it does happen within the next 2-5 years, which I think is quite possible, it will be the result of other additional influences pushing either China or the US to start something. The main possible trigger would be internal strife in China. If China starts melting down economically or politically, watch out. That's when I'll really worry because then they would have a real incentive to make a move on Taiwan -- to distract internal attention from the government and to build nationalism for the purpose of countering internal problems.
There's also a possibility that there could be an initial, limited exchange on one of these outlying islands. The Pratas Islands, Kinmen, Matsu, any of these could serve as the location of a 'trial' war, a testing of the waters of sorts.
Or, as you point out, the trigger could be an accident, and the powder that it ignites, and hence causes war, would be the range of other motivations, i.e., stagnating economy, internal political tension, and a fear of losing momentum in their conquest of the South and East China seas.
One thing is for sure, the world economy is in a tailspin and it's not recovering, nor will it for another year or two.
Another possibility is that the US sells Taiwan out, something the US has shown it's very willing to do around the world. If the price is right, the US will turn a blind eye and let China put up a naval blockade, and from there it's a done deal.
The long China game that doesn't call for war but would, I think, work for them would be to just buy off each generation as it graduates from college, a carrot and stick approach. Strangle the economy, and throw graduates a lifeline with jobs in China. They've been doing that already for years and it was working to a degree, but then they shot themselves in the foot by screwing over HK. That served Taiwan's interest.
So who knows how it will play out. I'm not optimistic about the situation.