I was in VN+Thailand for work recently.

Private sector White collar salaries in VN, Thailand, and India are roughly comparable.

That said, there isn't as deep a bench of expendable somewhat English fluent software talent in VN or TH (largely due to the explosion in technical colleges teaching basic fizzbuzz in India and the lack of English medium education in VN+TH).

Both VN and TH are also clearly targeting South Korean and Japanese companies instead of American ones ime due to the 2013-17 Trade War between PRC and Japan+SK.