If Dubas had taken over as GM when the prior GM did with a team finishing last overall such records as this would be unachievable and unattainable.
Back in 2015-16 the team was winning 29 games a season and not 49 games a season as generally GMs take over from fired GMs on struggling teams like the previous GM did.
When your team is drafting 5th (Rielly), 7th (Kadri), 8th (Nylander), 4th (Marner) or 1st (Matthews) there is no opportunity for your GM to establish this type of record, but it sure is stocking the cupborad and building the base upon which to build off of.
You need to be handed over the keys with all that suffering and struggling and high draft picks in tow, and the table set and then build up a successful team for Dubas to have achieved this new record.
Dubas was the interim GM when they were dumping Kessel and gutting the team, where WINS was not the #1 priority, and had Dubas day #1 began back then this record wouldn't have been possible.
Right place and right time inheriting a team that just recorded 49 wins and was #6th overall in the NHL standings with all that talented core accumulated over all those down years.