Therein lies the contradiction of the op. The premise is that it's better to invest overseas, so they will use the tax code to prevent people from selling their US assets so they won't be taxed. Which is absurd other then as a temporary short term measure. In the long run, if overseas is better, the money will go there. We need to stop using the tax code to punish US companies, that will create jobs.
No the premise is the average investor is massively under-invested in overseas markets based on both the Harvard Portfolio and the foreign markets share. By eliminating capital gains tax, US investors will move massively to balance their portfolio since any friction will be gone. The result will be a disaster for US jobs.
If you really want to help US companies and grow jobs you would raise the capital gains tax to the level of the personal income tax and you would reduce Corporate income taxes by an equal amount.
Strangling movement of capital is not the way to produce more jobs. Making the climate here congenial for investing and working is.
If anyone were stupid enough to do what you suggest you would see stagnating industries producing meagre returns, often bailed out with taxpayer money. E.g. France.
I dont want to see us become France.