Is developing a “stage persona” old-hat?
Every generation naturally thinks the generation that preceded it is corny and out of date. Even the word corny has been changed by this new generation into the word “cheesy”. (Which used to mean cheaply made or flimsy, but now is substituted for corny)
But in the past, performers would spend years perfecting not only their on-stage patter, but their on-stage personas as well; honing both until it was a thing so unique unto themselves that few could even copy it. This was achieved by spending “time on the boards”, performing for live audiences. They added some new material along the way, yes, but more importantly slowly and diligently perfected the material and persona they already had.
Actually, many of the top magicians working today do indeed have unique stage personas. And even though they might not be household names, they make a very good living indeed. So, the stage persona is not quite dead yet. It is just making a slow transition, sparked by young performers, into something new and vital.