Agreed it is a much smaller impact than new construction per house but the numbers of resales are and always will be multiples higher.
I think the 10% number is about right between both sides (buyers and sellers). Average is about 5% comissions (split between agents, brokerages, transaction coordinators, assistants etc), then 2% closing costs (1% each side for title, escrow, notary etc.), 1% lender fees then we throw in termite work, home inspections, moving companies, painters, flooring, furniture, the fedex guy, real estate transfer taxes, lawyers, guns and money…..