You're just clueless on Thai traditional music or music in general that you couldn't hear how those songs were modern western music with tradition sounds blended.
Of course, Thaitanium is an artist, it can no way has as many reaction videos as all V-pop artists combined. I find reaction video pointless anyway. Views on those videos are mostly come from the country where the artist is from anyway.
Since you have already pointed out the Thai has different taste thus, the developed genres of music are different to compare a genre of music is kinda absurd. Dubstep is not popular in Thailand thus, it's lacking. Actually, the whole EDM scene is underdeveloped. But, if you like Synth pop, there are many nice artists.
Those songs are not modern mixed. They use western musical instruments, not modern mixed. When I talk about modern mixed means the use of traditional instruments or traditional opera sings using modern mix techniques. Not some traditional songs use western instruments. The Ground Break Tony Ya, that song is modern mixed tradition I am talking about.
The songs you called it Synth pop are actually New Wave, its' EDM sub genre which popular in the 80s early 90s but now day that genre falls out of favor.
The reasons Kpop popular is because it is sensitive to the trend. Hip Hop or EDM dubstep, bass drum, jungle, trance, house..etc. are big in Europe and U.S. Kpop is the Asian early adopter, incorporate with Rap, Choreography, and styling makes Kpop popular. While other Asian still stuck with their dominant genre; Taiwain, China ballad still a dominant genre, Thai is rock right? In Vietnam ballad is still dominant, and gradually shifting toward EDM in recent years many of good EDM mixed released.
For a music culture to be popular you need to be creative and sensitive to the trend. The trends mostly popularize by the West and U.S.