After reading ~10 different authors on self-help, you realize they're all saying the same thing. So no, your assumption is not true.

Yes, I did read a lot of light self-help books in the beginning, but their number in total is less than ~40.

It's totally not important how many books you read, but their quality, we agree about that :) That's why I mentioned it's better to read more times the same book, than more books on the same topic once.