Absent nukes, they don't do enough. They are a particularly expensive means of delivering HE to Taiwan.
And they don't put boots on the ground.
As for their accuracy, no one is entirely sure what off the shelf upgrades have been made with Russian and/or Loral/Clintonian assistance.
No one is sure that those "proving ground" figures will be anything matching reality, either.
Also, nobody is sure the damn things will work as advertised. In testing, where the missiles are extensively checked out and any problems fixed by factory technicians before launch, these things have a 75% reliability rate.
Absent such intense prelaunch workup, what's the reliability figure going to be?
In any event, quanatity has a quality all its own.
True. But without nuclear warheads, the "quantity" of missiles required would be in the tens of thousands.
Between their missiles, sleepers/SF, and their attack aircraft (yes, they're mostly elderly), they can disrupt Taiwan's response. Cause chaos. Sow confusion. Degrade capabilities.
Yes. But friction works both ways. And covert warfare has very finite limits on its ability to influence events. To take down an entire free society solely by blowing some stuff up and causing some chaos? Hell, if you get even slightly unlucky, you're liable to blow away the "accomodationists" you're relying on.
Compare this situation to that faced by the French in 1940 after the panzers broke through. The French still had the ability to resist, but their political leadership thought they were broken and an accomodationist/defeatist faction came to the fore.
After an attack that generated very large numbers of civilian casualties, "accomodationists" would be wise to keep their heads down and call for the destruction of the mainland heathen.
People mistakenly analogize Taiwan to Israel when it comes to their qualitative military superiority. The fact of the matter is, a lot of their hardware is rather old and they have a real problem upgrading it.
A lot of their hardware isn't old. They get a lot of time to practice with their equipment. And, unless they are dumber than a box of rocks, Taiwan has a sizable nuclear arsenal.
China, on the other hand, not only has a massive quantitative superiority, but also access to excellent Russian equipment of recent vintage.
And they get very little training time with it.
Furthermore, Taiwan's young people are creatures of modern culture. The garrison state mentality that existed in the early years is gone. If China were to move on Taiwan, there would be some in the public and the government who would advocate taking a HK deal.
Ah, the standard "the youth are weak and decadent" line favored by all totalitarians.
After a massive attack, anyone advocating taking a HK deal would be tried and found guilty by the Honorable Judge Lynch Mob.
It's a question of will, that's the true center of gravity.
If Taiwan's will holds 48 hours, then the ChiCom government is likely to collapse from a military coup.
And when someone randomly drops 950,000 pounds of high explosive across your island, apparently in an attempt to kill many civilians, the likely result is fanatic resistance.
Your whole theory of war is straight out of Giulio Douhet--and history shows that bombing civilians doesn't inspire them to surrender. It convinces them that their survival is bound up in winning the war. This explains the failures of the 1940 German air campaign against England, as well as the subsequent failure of the Combined Bomber Offensive against Germany.
No, I'm not advocating what a Douhet-style obliteration of Taiwan. It would be counterproductive and would tilt world sympathy to Taiwan -- and if you think the Euros were on our backs about Iraq, wait until they have to choose between a democracy and the "China market." The PRC would try to ape US doctrine and take out C4I targets. And from what's out there in the public domain, they seem to be focusing on cyber-war capabilities as well. They wouldn't have to be anywhere near 100% effective to gain an advantage during the first few days.
And just because they would be wise to have a nuclear arsenal, doesn't mean they do. I would, but hey, who knows?