I don't know if the OP is posting seriously or not...
The Cornwall is a horn loaded system. The bass driver is not a subwoofer. It's called a woofer. The drivers are well made and can take considerable abuse compared to home speakers of today.
Klipsch speakers you find at Best Buy are quite different from those designed by Paul Klipsch! He is rolling in his grave today at the thought of overseas labor (slaves) assembling plastic parts - cheap knockoff designs of the real thing!
Take a look at the old, original compression driver and compare that to one of those wimpy horns you see in the new stuff. There is no comparison.
Efficiency? You got it with the old speakers. The new ones just don't have a BIG sound. Bass is exaggerated, loose and out of control most of the time and quite non musical. A kettle drum should have a tight dry sound not a rolling sound that flaps like dumbo farting in an oversized rain barrel. Elephants should not eat Taco Bell...
You can get parts and repairs still for these speakers! Hold on to them and fix them up! Many third parties out there offer services and are highly recommended.
http://www.critesspeakers.com is one such place.