I did when I was relaxed...but only because thinning hair runs on the women on my father's side.
But now I see that in addition to genetics, they also had unhealthy hair practices like scratching their scalps with hard combs every week, relaxing bone straight every 3-4 weeks, using marcel irons on relaxed hair, sponge rollers. Etc.
My mom's side has beautiful hair and their hair care practices are very different. They are ALL Naturals who roller set every week. Rarely use heat. My mom never used chemicals. I still don't know why she relaxed my hair.
Now that I'm natural and take care of my hair, it looks like a different head of hair from when I was a kid. Even my mom says so. She's always asking me "is that your hair?" .....lol. Yes Mom. Yes it is. This is what my hair was capable of before you "permed it".
All that to say, I think healthy relaxed non thin hair is possible with the right care. Just Use Meticulous care if you have a genetic predisposition toward thin hair. If you listen to your hair, you will be fine.