What caused all the problems?
I can’t say for sure but I have a pretty good idea. There were rumors of corruption among the construction management at the airport for some time. Someone wrote into a blog anonymously and said he was a successful bidder on a portion of the construction but was asked to give 40 million baht (a million dollars) as a kickback before proceeding. When he refused he lost the contract. I don’t know if that was true but it certainly fits the pattern of a failed construction project.
A contractor who has to pay a huge bribe in order to get the contract is going to have to cut corners to make money on the deal. The manager who has taken the bribe will not be critical of the work he inspects.
Again, I don’t know if that’s what happened, but it fits the pattern.
I also must say, I have never personally seen corruption in my three years here in Thailand.