Debusschere was absolutely the lynchpin to the Knicks brief but spectacular glory years.
The amazing stat is what the Knicks record was before acquiring Debusschere, what it was during his Knicks tenure and what it was after he left.
Before the trade the Knicks had ten of eleven seasons well below five hundred (278-474 total regular season record during those eleven plus seasons until the trade). They were 18-17 in the 1968 season when they traded for Debusschere on December 19th, 1968.
After the trade, things immediately clicked for the Knicks and they went 36-11 the rest of that season. For the next five seasons the Knicks won 266 additional regular season games (53.2 wins per year), were always well over five hundred and won two NBA championships. The regular season record for the Knicks during the Debusschere years was 302-155.
Debusscherre retired after the 1973/1974 season and the Knicks immediately reverted to their pre-Debusschere form. Over the next 14 seasons they had ten losing seasons and only one season where they hit the 50 win mark. Over those fourteen seasons their regular season record was 516-634.
Frazier, Reed, Barnett, Bradley (later on Monroe and Lucas) were all time Knick greats, but without the lynchpin, Dave Debusschere, the Knicks greatness of that era probably never occurs.