i wish i could understand how cats became so popular, given -> Fleas.
As far as i can tell, anti-flea treatments have existed for about 50 years.
I get that catching mice is a huge plus, but a house full of fleas also kinda sucks.
Anyway, if your house is loaded with mice and rats, you will also have fleas. Unlike the rodents, your cat will even let you comb it.
Also people weren't necessarily clear on fleas or whatever being something you caught. They were more seen as things that just showed up under certain circumstances.
1) I think you underestimate how bad a rodent problem can get, and how quickly.
2) Healthy cats are decent groomers, and also flea magnets. Fleas go to them preferentially. If the cat isn't a lap cat and doesn't sleep on your bed, it's going to be doing most of the interacting with fleas while you relax in your mouse-free study.