Is thin hair more susceptible to falling out when combing/wearing tight hats vs thick hair

I'm wondering if thin hair is more likely to fall out via tension vs a thick terminal hair

I'd certainly say so, yes. Thinner hair is more brittle, thus more susceptible to breakage. BTW, from personal experience, excessive combing and wearing tight hats were 2 main factors in causing my hair line to prematurely recede. They both promote inflammation byway of friction and mechanical stress. I believe these follicles don't regenerate so well due to DHT slowing the conversion of KRT-15 stem cells into CD34+ progenitors, but chronic inflammation exhausts the store of PC's within the bulge.

If I could go back in time, combing and wearing tight hats is something I would have avoided completely.

Don't buy it completely