I think they are referring to the fact that software development as a field has matured a lot and there are established practices and experienced developers all over who have been in those situations, so generally, these days, you don't see such code bases anymore.

That is how I read it.

Another possible reason you don't see those code bases anymore is the fact that such teams/companies don't have a competitive comp, so there are mostly junior devs or people who can't get a job at a more competent team that get hired in those places