Unfortunately mid-range clients these days want it all. Unless you can serve it up with a smile, then they'll find someone else to do it for cheaper.
So where are they going to find someone that can do it cheaper using the same quality in lenses?
Possibly your biggest competition here would be someone that's bought a set of Zeiss CP lenses some time ago and the cost of those lenses has now disappeared from the books. They can just mount them with an adapter and using the Zeiss shims to get the focus right.
The problems you face here have got nothing to do with the price of Canon's lenses and everything to do with the way you run your business and market it to customers as there's nothing stopping you from shooting cheap like others do except yourself.