Well, naturally. But remember you need two containers, one for commingled, one for junk mail, so that's triple the number of 45-gallon carts (they come in all colors of the rainbow, btw) that the city needs to provide now. A fairly large investment.
Also realize that the advantage to the 45-gallons is they can be lifted by the truck's compactor and dumped into the hopper semi-automatically. Most residents' recyclables volume doesn't justify the need for semi-automatic collection, and hence the need for 45-gallon carts.
The small city-provided bins are easy enough to lift by hand (although too small for my needs). A wheeled refuse container is also quite liftable, even when full of recylables. And they're not all that expensive.