I agree that it's difficult to separate.
One could argue that players have never been more skilled, simply because the skillset keeps expanding. And that this will likely continue going forward.
When it comes to talent though, it's a bit murky, because that talent is also between the pipes, and on the blueline.
Either goalies have suddenly become terrible despite all of the advancements in goalie instruction at increasingly younger ages, or there's something else at play here.
I think there are too many players in the league nowadays for "more offensive talent" or "less defensive talent" to be a major driver in what happens with goals per game.
It's more likely in my mind to see sweeping changes, like the crackdown on obstruction that led to the post-DPE era (more PPs initially, less hooking now, which is to the detriment of defensive play), the proliferation of composite sticks (which have no defensive advantage), or the shrinking of goalie equipment (which can only benefit scorers).
Meanwhile, the post-80s DPE came about with fewer and fewer enforcers playing regular shifts on the bottom lines, the emergence of better skating bottom-six players specializing in defence, the introduction of the trap across the league, the increasing size of goalie equipment, and the reliance on obstruction (see: can opener) as a legitimate defensive approach.
I see that some people like the big round numbers without context, and that's fine. I just prefer to interpret those numbers with a little more context.