I can't speak for anyone else, but my experience was:
As for testing everyone at the airport, that'd create significant congestion. It's one thing to deal with a relatively thin stream of arrivals into Phuket, quite another at a major hub like Bangkok.
- Go to skyscanner.net, buy tickets
- Go to COVID-19 travel insurance for Thailand Pass (2... :: AXA Thailand, buy insurance
- Go to agoda.com, buy test & go package
- Go to tp.consular.go.th, upload flight details, insurance policy, Agoda test & go reservation, vaccine card
As for testing everyone at the airport, that'd create significant congestion. It's one thing to deal with a relatively thin stream of arrivals into Phuket, quite another at a major hub like Bangkok.