From the bottom up:
I'm not going to say I agree with you, but...
Well, transportation is not, to most of China, difficult, thanks to the reforms of the past six years that introduced the first regular flights over the Strait. The next step would be opening some sort of representative office here to improve communications, lower the chance of misunderstandings, and (from a selfish perspective) allow me to apply for a PRC visa without needing to go to Hong Kong first.
That is a risk. But is it better to let them disappear entirely to make way for new high-rises? Or to let less-than-qualified craftsman patch them up because the city government won't/can't afford to pay professionals to do the job?
That may be true, but stability, security, a sophisticated population, and relaxed laws are also very appealing. Meanwhile, homemade brands would have more ability to and more protections in selling products to China, and vice versa.
Free trade may not be a panacea, but when South Korea is sending parts to China for assembly and then shipping completed consumer electronics to Europe and North America without any tariffs, export-driven Taiwan will find things getting even worse.
A survey of world politics over the 20th century shows that allegiances change. It's impossible right now to imagine Taiwan facing an external threat from anyone but China, but that doesn't mean it will never happen. I personally think being defended by the PLA would be much more a burden than an incentive, but I'm just throwing this out there as a possibility. Who knows, 50 years down the line, if there will be a new empire looking for global expansion?
That's not what I meant. In the Guangdaxing shooting, for example, Taiwan had a hell of a time convincing the Philippines to do anything within their own country. They're likely to have a hard time getting Vietnam to do anything about compensating the factory owners who had their facilities looted. (Vietnam is, supposedly, contractually obligated to do so.) Again, Taiwan's major enemy/rival is China still, but should that change, Taiwan might find it comforting to have a strong negotiator at its back when dealing with (future) hostile parties.
Again, to clarify, I'm not a supporter of unification. But neither am I a supporter of independence. I just want to the Taiwanese people to set aside their visceral reactions to both of these concepts and think about them realistically, then make a rational decision. Whichever decision it is, as long as it's based on reason and earns a large majority of support, I'll be behind it.