As a Cornell fan I agree with this mostly.
The "manufactured to replace" is a little strong. Harvard was actually Cornell's first significant hockey rival, several years before the big rivalry with BU began. The Laing Kennedy win against Harvard
in 1962 is often considered the arrival of Cornell as a meaningful hockey program (just a coupla years removed from being
outscored 31-0 by the Crimson in a pair of 1959 games).
It is more accurate to say that when BU left our second-best rival simply moved back up to #1. This was of course only from Cornell's POV. AFAIK Harvard has always considered Yale to be far and away its most important rival.
During the relatively brief period in the late 60's and early 70's
when Cornell and BU annually duked it out for national primacy that was one of the best rivalries in college hockey history, considering the mutually loathing and the stakes. Since then we haven't really been part of a truly transcendent rivalry. We are more the ECAC's Minnesota, Michigan or BC: the team with the obnoxious fans that everybody else in the conference derives special Christmas joy in beating.
The best rivalry in the ECAC is far and away Clarkson-SLU.