While the lack of daily housekeeping means that trash piles up in rooms and hallways, that it’s tougher to clean rooms between guests since the rooms become dirtier, and thus it’s more likely new guests receive dirty accommodations, as long as hotels meet basic cleanliness standards it’s hard to see making daily housekeeping a law.
Nonetheless do not ever believe a hotel chain or lobbying association when they say their practices are intended to benefit the environment. And here remember that the biggest advance in the history of public health that extends lifespans is cleanliness.