It doesnt work in BKK and Pattaya - there are plenty of places you can drink until dawn in both, it does take a bit of inside knowledge but doesn't take too much effort to find these places. Speaking personally I don't like to start drinking until 10pm at the earliest - what I want is the choice of when to go home - when I used to have the bars I sometimes batted on till dawn if I liked the company and sometimes I used to shut on what ever the closing time de jour was.
I've seen this closing time lottery all too often and I'm not complaining about the change - what I am complaining about is being dictated to when to go out and when to go home, and no Trent I never drink at home - frankly these days once or twice a week in the right company does me fine.
As for Chiang Mai - I have no idea - nightlife and bar closing certainly never entered into the equation.