Thats a good question. In my mind, commercial cleaners may own more equipment, designed to work on LARGE areas. Residential cleaners normally dont need that sort of equipment. For example: some commercial buildings have very high ceilings. The cleaner may need equipment that will raise them up to a level where they can clean - say, light fixtures, etc. A residential cleaner seldom needs this sort of thing. Residential cleaners clean on the same eye level as the customer. I always tell people that if they have very high ceiling fans, I may not be able to clean them well. Commercial cleaners may need several employees to insure that all the work gets done. Many house cleaners do NOT need other employees. A "cleaning company" does hire people who do the work for them. And this may not always be the best thing for the customer. Of course, I am biased, being the sole owner and worker in my residential cleaning business.
This is all just my opinion, and others may not agree.