Injection-molding the plastic housing is a lot more expensive than stamping steel for your typical can oil filter.
The cartridge filters work fantastic, and sit in the engine, rather than being external and hanging off it - so less oil is needed. They're also a bit lighter, and easier to package. They filter just as well, if not better. But yes, they do cost more.
I usually pick up a Delco filter for the Cav for under $4 at Advance Auto, while my Cobalt's filter runs about $7-8 for the Delco. It evens out, since I run the Cobalt's oil twice as long.