Not only how poor and abundant the population is.

'Money is the first thing. Morals follow on.' (based on B. Brecht)

From Wikipedia:

Democracy Index 2021: Vietnam 131 / China 148 (Norway 1 - best / Afghanistan 167 worst)

Freedom In The World 2021: Vietnam 167 / China 184 (Finland 1 - best / Syria 194 - worst)

Where were Apple Watch and MacBook made before Vietnam? Is the answer just China and nowhere else?

How much does it cost in that location now compared to what it's going to cost now to make it in Vietnam?

How many Vietnam workers is this going to employ, and are they going to be working for like... $3/day?

Apple Watch was China. I think MacBooks where partially made in the US, but I could be wrong. My understanding is the MacBook line (and everything other 'mature' product line) is heavily automated now.

Foxconn employs 1.2M people in China. And Pegatron, 120k.

So... a lot of people.

More like $20 a day. But its still dirt cheap compare to developed countries.

for how many hours a day, with what kind of PTO/benefits?

Nice question! To earn $20 a day they certainly would need to work overtime. And there is almost no such thing as benefits.

The main criteria for every electronics company, singleing out Apple is just BS.

Yes, but this particular news is about Apple.

Vietnam is not that poor. Vietnam is MUCH richer than its direct neighbours, Laos and Cambodia. Thailand is richer though.

The actual thing is not really poor population, but how easy is to build new factory there.

Vietnam has the best thing for that - it is easy to build new stuff there, as the infrastructure exists; however, they absolutely ignore any environmental laws and just spew all waste into rivers and air.

Look up Formosa Steel incident - https://en.wikipedia.org/wiki/2016_Vietnam_marine_life_disas... - huge disaster of a Taiwanese company, after which there were big protests. Communist government then arrested all protesters and put them to 20 years in prisons (for protesting against a foreign company!). Nobody protests about environmental waste now.