I don't know to be honest but I have seen the changes coming gradually over around the past decade. When i first moved to Thailand in 2004 it was similar to the way the visa system in Vietnam is now... they just let anyone in.

I know my opinion is jaded because I am a bit anti-government in a general sense but I think this might be a case of 'over-managing" the situation. The saying goes "if it isn't broken the government will fix it until it is!"