For someone who has an audience like this now, I don't get why he doesn't do an actually different and interesting version of it. Like, do a drum cover with a twist, not just "in MP style" over an over. I feel the guy is missing his chance to raise his standing.
In fact he is occupying a niche. A lot of bitter people who feel the need to watch his videos to say "Wow, it's so much better with Portnoy style!". Again and again and again. This generates likes, comments, views.
He is trapped inside this MP-stylevarium.
Personally I think interesting because this whole history says a lot about music, musical appreciation, fanbase, subjectivities, etc.