I always thought of GST & VAT as a citizens tax and not a corporate tax. In Australia at least, GST income can be offset by GST paid, so it's the end user that bears the cost. I could be wrong, but that's how some of the tax guys talked about it.

Anything to do with taxes is about political will and who the government can poke more till they get pissed off. Typically it's the citizens that feel that brunt, especially the low to mid income worker bees. High net worth individuals & companies have the ability to relocate (i.e. French relocation to Monaco for the negligible tax rate), while the worker bees are sort of stuck.

Lastly, dual taxation is on a country basis as I am pretty sure my colleague who was seconded to China for a year had to pay taxes in both Australia & China, but the company covered the China taxes. Some countries have a reciprocal understanding, but not all.