How do you suggest that hosts factor it into a nightly price? I promise you we would if we could, as this conversation gets tiring.
Hotels employe cleaners on a daily basis on an hourly price, and hotel rooms only take maybe 30 minutes to clean. Airbnb is totally different. Single properties, paying separate cleaners and laundry services, that have to travel to/from the property, and then spend a few hours there.
Airbnb SHOULD just take the cleaning fee hosts charge, and then average it out over the number of nights on a guest's stay. They don't offer that option.
For hosts to try to use a crystal ball is impossible. If hosts just add a flat fee per night, that would be mean guests staying one or two nights perversely pay far less for cleaning then guest who stay for two weeks. That's unfair. As it costs the same, and longer stays should be rewarded, not penalised.
If guests have an issue with this then hotels are available. Putting pressure on hosts in this regard leads on to a squeeze on pay for cleaners who do a really hard job for already poor pay.