this has gotta be the answer. I have the exact same experiences and feelings as you. I always look for basically the cheapest Airbnb and it ends up cheaper by 2-3x than local hotels and I've never had an uncomfortable stay. What I have had are completely normal rooms in working class homes - which is fine because who the hell cares about enjoying the hotel room when you travel!
My impression is that virtually all of the Airbnb complaints (both from guests and from neighbours) relate to "entire apartment" listings and/or the "private rooms" where the owner isn't on site.
There was once a time when most of the listings were for spare rooms in someone's house/flat, and to me that was kind of the whole point of Airbnb in the first place.
In recent years we run into more and more listings where somebody renting out the entire house, each room to a separate individual. Sometimes it is indistinguishable from the former one before you arrive. If I staying at a "hostel" I want my bathroom and kitchen cleaned every day, but most likely I would just choose a real hostel.