In countries that are seeing an increase in tourism the tourist authority should take a close look at what they are doing. Maybe then they will see what is causing the downturn for Thailand. It wont just be a single factor, it will be a combination of several things. TAT needs to look at all the factors and see how they can at least equal them or better them. Sitting and complaining that tourism is decreasing without looking at the reason why is ridiculous.
Look at what attracts and promote similar. Look at what is harming the tourism in Thailand and scrap it or at least radically modify it.
Thailand has all the tools to make it the greatest destination on earth but no use having the tools if you don't use them.