I think the Washington "model" is actually the Dallas Stars "model", but Dallas just doesn't get credit for it for some reason. Which is really weird because Dallas is actually a legitimate top contender now and clearly demonstrated how to transition from an aging, mediocre team to a top young contender without relying on high draft picks.
In the 2016-2020 window, Dallas was a good but not great team led by older guys like Benn, Seguin, Bishop, Radulov and Pavelski. The only really notable young guy they had was Lindell, everyone else was just a depth guy like Faksa and Nichushkin (who stunk in Dallas if you remember). But they just kept drafting well and gradually adding more and more good talent to the team, with first adding Hintz and Heiskanen near the end of that window and then consistently adding 1-2 "core" level young players basically every season. Now they have an entire core of top young guys that they drafted, plus they're able to add to it externally with guys like Rantanen because of how good of a job they have done.
Dubas is calling it the Capitals model because they're the most recent team to do it, but what he's really trying to recreate is how the Stars built up their contender. Get a lot of picks, draft well and then be aggressive to add NHL talent with the assets/prospects you've collected when you get the chance.