You're telling me. A lot of people don't take the concept that seriously. Sure, it's a weird idea, but so is Mario itself. The fun in making stories is that you take the weirdness seriously.
I have no idea either. Though I would like to see him make the “It’s a Stone, Luigi” joke again; this time with Classic Mario and Luigi models by JCThornton and a Classic Yoshi model.
From what I remember Nova saying is that he thought his videos were cringy and not polish, and will be deleting his channel. Personally, I thought his videos and animations are great and very entertaining. I really hope he returns and goes back to making animations, but till then I hope he's doing okay.
