How do we define zero?
Because my experience is that since 2E, you just don't normally start as "zeroes", and I feel like most of the people claiming they are doing "zero to hero" have a creative definition of "zero".
From 2E onwards, a PC likely starts with a race with serious abilities (unless human), a class which is not helpless at level 1, and on top of that a kit and skills/proficiencies that often make even a level 1 character kind of formidable.
3E, 4E, and 5E obviously continued this. A 5E PC of level 1 is probably tougher/more dangerous than most level 3 1st edition PCs, for example.
So unless we redefine zero as simply "a term for level 1", I don't believe most people who are claiming to go "zero to hero".