Well, my wife noticed me some 26 years ago. I’m sticking with what works!!!
Can’t remember a time when I wasn’t invisible to women.
Probably the women who noticed you weren’t flirty.
When an unflirty woman notices a man, most of the time he isn’t paying enough attention, or maybe he’s too shy, to pick up on her very subtle hints that she is attracted to him.
Eventually some guy WILL notice her after others have been oblivious to a very good catch.