2024’s spread is almost identical to 2020’s. just without Florida(which was still considered a swing state then). 2016 was a broad year with something like a dozen states considered gettable, and a couple states that ended up flipping weren’t even supposed to be swing states. 2012 only had a handful, I think even fewer than we have now, like 4 or 5. 2008 was another broad year.
Only way it can change is either if a swing state tilts hard enough to no longer be one(Michigan being too blue) , or a formerly safe state tilts enough to be up for grabs again(something like Virginia or Texas)
There have also been periods of American history with basically no swing states and the bulk of the country up for grabs with only a couple of ‘safe states’ each if that, the 70s and 80s didn’t really have swing states, neither did the Depression Era, but I don’t think it’s trending that way