Why would a wealthier tourist come to Thailand? In most places, it's dirty, the smell of sewage is constant, the traffic is life-threatening, and the people are no longer friendly. In fact, many Thais dislike foreigners ("farang"). You get scammed everywhere, and the quality of services and service is declining. Yes, of course, there are beautiful places in Thailand that you can enjoy without mass tourism, so that's not the issue. As long as the folks in Bangkok drain the state treasury and don't seriously invest in their own country, the quality of tourism, and consequently the quality of the country, continues to deteriorate.