Yea it's the end of an era, but it's also a work in progress. Meaning it's not over yet. Frank Williams is still there, more retired than pushed aside. Ron Dennis was there until a few days ago. The things he personally put in motion like Alonso and Honda will be there for years to come. Bernie, my god Bernie!!, has outlived almost all of them and is still there doing Bernie things ("If they don't like the terms then they don't have to sign, but it's take it or leave it"). Keke Rosberg's kid and Jos Verstappen's kid are frontrunners. Adrian Newey is still doing wizardly things with the cars.
It's the ending of an era, yes. But not completely done. It's roughly analogous to an American Baseball fan in 1935 saying it's the end of an era because Babe Ruth was retiring. All true, but baseball continued to make many classic eras for the next 80 years.
That's how I'm selling the change to myself. Not sure if it's sticking.