Dear god, you guys really love to point out 'it's really only 66 seats'. Sweet, wanna point out how cool the Economy Plus is as well! The airplane was bought almost entirely to make a generation of mainline metal redundant. Upgauging from 50 seaters has rarely occurred in comparison.
A CRJ700 can't compete with a 737/MD80/E195 head to head because it simply costs too much to operate. So no, that airplane wasn't bought "almost entirely to make a generation of mainline metal redundant."