Starting November 20, your Airbnb host can't make you strip the bed or do the dishes before you leave. Hosts are threatening to quit over it. Airbnb isn't budging, because it's basically turning 8 million homes into the biggest hotel chain on earth. Marriott is the biggest hotel company in the world, and it owns or leases only about 1% of its 1.8 million rooms. Other people own the rest. Those owners pay Marriott fees and run their hotels by Marriott's rulebook, and Marriott gets to decide how…