Healthcare in Thailand isn't as cheap as it's made out to be, maybe only if you're American. I have 2 old friends who are back in the UK now, one in Liverpool, for cancer treatment. An old Irish friend had cancer treatment in Bumrungrad that cost £38,000, how many expats have that much spare cash? Another (very wealthy) friend made around 5 million Baht on a property, he ended up giving all of that to B'grad, according to a mutual friend.
Ciggies in Cambodia are way cheaper than in Thailand. Half a draft lager 50 cents in PP (is that about 18 Baht?), where will you get that in Thailand? Many expats are counting every penny.
Visas are also way easier in Cambodia,