I'd wager that qualified support staff would get paid well over $20/h. Plus there is all sorts of business overhead.
In all fairness, support costs also include all of the techs' phones, computers, networking, software licenses for Teamviewer et al, and office overhead. So a $20/hr bill is pretty cheap for a minimum wage technician.
Hell, I am just a sysadmin/developer with minimum experience (2yrs) and make ~$32/hr.