About the number of troops needed, I'll just say once the sea lane is secure (how much ship attrition after normandy? zero?), and heavy armor is onshore, PLA considers the battle as good as won. Why? From the very start PLA believed it could handle USA in Korea, pitting peasant army against the most victorious power of WWII. Who else would have thought the same? PLA was right. In fact it has been right in just about every strategic decision since 1934. So I tend to believe when PLA says it can handle the Taiwanese army.
Ok, need to go over a few things here...
Goldenpanda, how many troops do you expect the PRC to need in order to gain control of Taiwan? Part of the idea behind trying to determine the number of troops was to then, based off that estimate, make estimates on force & logistics requirements to achieve the estimated number. For instance, if the PRC manages to gain air/sea control, and even manages to land troops (say all 250 troops * 25 vessels =6,250 troops) the PRC force would not be able to take control of Taiwan, there just wouldn't be enough personnel to do so. It then becomes a question of the total# of personnel and equipment needed to be moved by the PRC to Taiwan, which would be subject to potential attack while en route. The question of whether the PRC could take Taiwan, and what the cost might be, is an arrangement of complex variables, which interact and effect each other.
I'll just speculate on some possible reasons
- Taiwan's drafted army are not eager to destroy their own homeland
- Taiwan has no strategic depth. They have no room to regroup, no breathing space after any breakthrough.
- PLA has better equipment and air superiority (as a precondition to their even being in Taiwan)
- PLA will simply fight harder and tighter, given its combat history. Why *should* Taiwanese fighter any harder than, say, the Dutch against the Germans?
With regards to your first and last points. Yes, an army is not eager to destroy their own homeland, however, a defender is likely to be fair more motivated in protecting their home and family than an attacker.
Given the small size of Taiwan, yes the Taiwanese don't have much strategic depth to fall back on, but there also isn't a great deal of room for the PRC to maneuver in. Not to mention that by constricting the size, it could potentially allow Taiwanese forces from different areas to support and/or re-deploy more easily than if the area was larger.
Also, what in the PLA combat history supports an assertion that it will fight a modern engagement better/harder than Taiwan? Comparing Taiwan vs. PRC to Netherlands vs. Third Reich is hardly a close comparison. The Dutch didn't have a large military relative to overall population. There wasn't a defensive terrain advantage for the Dutch, which is why Germany invaded the Low Countries, so it could launch an attack on France through the Belgium border. Also the Germans had built up their armed forces to be both better quantitatively and quality-wise than the Dutch.
As for the PRC having better equipment than Taiwan, that is open to question. There isn't a doubt that there is more PRC equipment than Taiwan, but it is questionable whether the quality of what the PRC has is better and also how much the PRC would actually be able to use against Taiwan.
-Cheers