The Alaskas are large cruisers. They are enlarged Des Moines more than they are downsized Iowas. They are what would have happened to heavy cruisers if there hadn't been a WNT, much in the way light cruisers went from 3000t ships with five 6'' guns to 12000t ships with twelve 6''
And the USN didn't invent the large cruiser concept. Fisher did, with the Courageous class large cruisers. Replace the two twin 15'' in the Follies with three 12'' triples and you have a WW1 Alaska.
This has always been my issue with the
Alaskas, they weren't really useful for anything by the time they were laid down, and even when conceptualized were less useful than the
Iowas (which, while rightly considered to be the best BB even built in many respects, was more of battle cruiser in the G3 mode) in any practical measure. The
Alaskas cost 3/4 of what a BB-61 class ship did and they had a operation life span less than 1/10 as long. Choosing between two more
Iowas or the three
Alaskas is so easy as to be a given. The less often mentioned option, of building either six
Baltimore class CA or NINE
Atlanta/San Diego class CLAA also makes vastly more sense.
The "large cruiser" concept was a bad one, something the RN figured out two decades before the U.S. even started drawing up plans for the
Alaskas. The were terrific for the value of what they were, true pocket battleships, especially with the superb 12" gun they mounted, but what they were was of so little value being the best at it doesn't really matter.
Regarding the never built, at least for warships, I would agree with it being the G3. Magnificent design.