hmmm maybe! I have never met a cat named Tabitha but the tabby cat thing could be an explanation. Still I don't really see why that would keep so many people from using it. Chloe and Sam seem to be super common on pets and people use them often. Maybe it's too old lady-ish?
But the litte girl from Bewitched was super cute and she made the name common. It entered the top 1000 when the show was first aired. It was even number 100-something in the 70s and 80s and then from 1992 on it started falling.
I don't get it, I mean Sarah Jessica Parker used it so I thought it would rise. Not that I mind that it's uncommon it just confuses me a little. I actually think the witch/cat association is cute and I like the nn Tabby.