It's not breaking even, right? The domain was 13 million. It makes "almost 7 figures" a year. So in 13 years, assuming that people still keep visiting a bogus site, it will have paid for the domain registration.

If you just want to break even, you should probably just register a google.com typo domain for $20, and then you need a lot fewer visitors to break even.

I wonder if some of them come from people "searching" from the address bar, or even from search engines?

(Google results for "sex" are kind of funny.)