This is interesting - I once spoke to someone who said the crazy cat lady number was 10. Having been to quite a few houses with cats though, I can say that some people have multiple cats are their house is very clean. You wouldn't be able to tell there were cats. I've also been to houses where there have also been one or two cats, and it stinks. The worst cases are the hoarding cases - and honestly, I don't think it's a crazy 'cat' thing. Unfortunately in those cases, I think many of the people have other issues to deal with - the cats are just one component of the issues. They can (and often do) hoard many other things too.
Tidycat is having a contest to debunk the crazy cat lady stereotype - and high time too :) Here's the website that was referenced in the article. Unfortunately it's not open to residents outside of the US but it's certainly interesting nonetheless!