Thaksin's 2001 and 2005 governments launched programs to reduce poverty, expand infrastructure, promote small and medium-sized enterprises, and extend universal healthcare coverage. It is hard to imagine they forgot all that but the young ones who don't know history may not remember.
However, he was elected a second time with an overwhelming majority in 2005 and I feel that is when the old guard turned against him for not playing musical chairs. He was simply too popular.
Westerners only remember his ill-fated, failed, war on drugs.