They can’t hold onto their own professionals let alone foreign ones. Plus a few things haven’t been mentioned here
People follow the money, right now the money is not in Taiwan, that’s why a lot of foreign professionals moved to China just like the locals.
The money concentrates and flows through Singapore/HK, due to their open market systems and low tax regimes. Basically they are cities that have become countries and due to their small size and lack of established agriculture/manufacturing/hinterland industry they are easier to control and change direction. They are also authoritarian regimes with only a veneer of democracy. I can’t take away from their well thought out policies though, especially Singapore.
It also has to be said that foreign professionals are , by and large, working for multinational or foreign companies. In general they would not be attracted, nor qualified or willing, to work for local companies in HK or Singapore.
Now if you want to compare Taipei and Singapore or Taipei and Hong Kong that makes a bit more sense. But again Taipei needs to follow the national structure, not a citystate structure. It also has strong and established local companies that benefit from the current regime.
Taipei actually has some advantages compared to Singapore and Taipei, namely cost and location. But there are many competitors for foreign investment and Chinese cities and provinces actively promote investment now mainly with the lure of the massive Chinese market and still low labour costs, although rising very rapidly in Shanghai.
It must be said Taiwan is a good base for running an Asian service centre. You can fly in and out directly to most Asian cities from Taoyuan/Taipei and even Taichung has a lot of direct flights to China now (pity about the airport…story for another time). Infrastructure is good, and costs are much lower than HK/Singapore. Taiwan is obviously a good choice for dealing with Chinese/Japan/Korean/Vietnam market.
Singapore would be a bit better for South Asia market. But if you are going to choose anywhere that has a good location for servicing the Asian market Taiwan is in a pretty sweet spot flying wise. Taiwan also has a pool of good Mandarin speakers and that should be an advantage as the service sector grows. Wages are relatively low in Taiwan.
But taxes are high on income here compared to Singapore/HK, so that discourages the higher earners moving here. And then the families usually prefer a place like Singapore which is really well setup for people not used to Asia.
How to get FDI to flow into Taiwan (and I mean real FDI, not the Taiwanese using Virgin Island companies to invest ‘washed’ money back here)? That’s a difficult question. The government have damaged the home market by promoting exports and income inequality over child friendly and labour friendly policies. The ECFA doesn’t seem to have made any difference at all in getting investment into Taiwan, a big failure in that regard. They have been too slow to push for trade agreements with other countries. They are behind the curve.
I think the biggest hope would be to attract more Japanese companies to invest here, and that is happening I believe. In Taichung the largest group of expats by far are not Germans or Americans but Koreans and Japanese. Maybe their best hope, and I say this with a bit of a sad reservation, is to pick up the crumbs from the Koreans and Japanese by virtue of being cheaper than them.