According to this study from 1970, cats are about 50% male and 50% female. Furthermore, there appear to be about 100 male pedigree cats born for every 92 female cats.
I couldn't find any info about sex ratios for cats that aren't adapted to live closely with humans. My understanding is that female cats occasionally live in colonies and work together to guard each other and their kittens. Female cats who do not live in colonies still hunt for themselves and their own offspring and protect their offspring.
Male cats...impregnate female cats?
It would take very few male cats to keep the species going. It seems like male cats don't do anything else beneficial to the species besides donate cat sperm to the females who take it from there.
I am wondering why, from an evolutionary perspective, so many male cats would continue to be born. Is this purely for genetic diversity purposes?