I don't need to lift my mattress to vacuum under the bed either

Of course you don't need pets for that. You just need a vacuum.

Why would I vacuum under my bed? That's where I shove items when I pretend like I'm cleaning the house.

I'm trying to teach them to hoover under the bed, but they refuse.

I have a bed similar to this, and it just gets a little dusty. I don't think I've actually cleaned it in a decade, and at most there's just a very faint layer of dust (I just checked) in one or two spots. What are you doing that a mostly sealed area is getting dirty?

It helps them wear more evenly.