Saying that the Golden age started with Action Comics #1 is easy.
Saying that the Sliver Age Started with Showcase #4 is easy. Well, for most people anyway
Saying when one age finished is not so easy.
The Golden Age finished for me when all the Superhero comics got cancelled, with only Superman, Batman and Wonder Woman running around at DC. If that doesn't mark the end of the Golden Age of hero comics, I don't know what would.
Yet, what the heck is that period during the 1950's? Where horror, true Crime, Sci-Fi, western, romance, etc ruled the day?
No one can agree as to what to call it.
When did the Bronze Age begin? For Superman that's easy, when Morty retired. For me and most, Mort as Editor IS the Sliver Age Superman, without him there is no Sliver Age Superman. Once Julie took over things change, the comic format change from 2 to 3 short stories per issue to one long story per issue. Also the artwork became more dramatic in that Kirby way (not art style, but in storytelling). Compare Swan's artwork in the Superman in the 60's to Superman in the 70's to see what I mean. The stories also started to get into the whole "relevance" movement. Jack Kirby leaving Marvel pretty much ends the Marvel Sliver Age. But, doesn't mean that Bronze Age comics are not as good as the Sliver Age, they are just different.
I think the problem comes in when people think of it like Olympic medals. This is one case where Silver and Bronze aren't necessarily less worthy than Gold. In fact, it's quite the reverse in many cases.
This is what Julian Perez is doing, one Age is not automatically better than another.
I respect the Golden, Sliver, and Bronze age equally.
It's only the Iron and Dark Ages that came later that I have a problem with, and even they were not ALL bad, just mostly bad, IMHO