@George ********
not many would want those jobs anyway. There surely are jobs around of you're qualified and have the degrees they prefer (ans I mean beyond teaching English...) Also it's not only jobs a Thai person can't do. They can do a lot of the jobs I've seen (most really, even if NES tend to be better at English in general), sometime's it's actually based on your merits more than where you're from, especially since we usually cost more to hire to get a WP through for jobs beyond teaching.
Sure sinsot exists, but what was stated before (that you can get most back after) is also true. It all depends on families, their local traditions (isan/south/chinese-thais/khmer-thai/lanna etc) and of course more often than not socioeconomic standing.
If someone has an agreement they're happy with then that's all good. As long as both parties agree and understand eachother I see no issues 🤷♂️