How much cleaning fee depends on the local market price of cleaning. Depending on how big the place is, $150 is possible. In SF e.g. you can't find a cleaner with $20-30. Hotels pay less on cleaner labor because it's more efficient (cleaners are probably full time employees cleaning all rooms every day anyway). And why it would be % of night rate? Cleaning fee is flat for one cleaning service.

Only makes sense if the host is actually paying professional cleaning service, or doing it themselves at the level provided at those services, after each stay.

And I am very sure that's not the case 99% of the time based on my own experience. I'd be thankful if the kitchen counter is clean and there is no trash. That's actually not a low bar.

You've stayed in 100 Airbnb's and only one of them had a clean kitchen counter and the trash taken out? That's dedication to a service and also extremely bad luck.

All the vrbos we have been at were professionally cleaned. Maybe the low end is more scammy

The owner can clean it themselves or the cleaning fee should be built into the overall price, you know, like hotels.

It costs about 200$ to get my house cleaned so it seems like a pretty standard cost especially for a larger place.