The idea that players all make their characters in isolation and just show up on session 0 with them sounds like such a recipe for disaster. I know it can work sometimes, much like "just grab four things from the fridge and throw them into the soup" can work sometimes. But sometimes you get like gummy bear pizza bites with shrimp and mayo topping.

I think a lot of games that came after D&D figured out solutions to common problems, but D&D insists on staying kind of archaic.