Superhero stories can’t get enough of making derivatives of the same big name hero. Keep in mind that every other story outside of superhero storytelling have done similarly, just not to the same degree. Jojo’s Bizarre Adventures circumvents it by handling it over to a new protagonist each story, with the old protagonists being marginalised (this is also the case with the newer storylines however with somebody’s brother).
Superhero stories by contrast creates multiple versions of the same superhero living in the same setting. They even get their own titles running concurrently with the main one. Not that there’s anything wrong with having multiple versions of the same character but marginalisation’s inevitable given the situation and which character to prioritise. If Superman gets prioritised, then Superboy and Supergirl would either be minimised or cut out altogether.
So it’s like Jojo where each storyline gets renewed with a newer protagonist taking place. Except that DC still wants to make Superboy and Supergirl as important as Superman but aren’t sensible enough to realise it.