There's an interesting little article in the Bangkok Post on the current oversupply of hotel rooms in the city
http://www.bangkokpost.com/business/...a-pathnadabutr
I have also been baffled by the sheer number of hotels and new projects in the city and how they can all stay in business. But the article notes that occupancy is decent on an average basis anyway. It's great for us visitors as it keeps rates ridiculously cheap.