Both the USN and the RN had turned away from the 8-in armed "Treaty" heavy cruisers which really were a response to the Naval Treaties of the 1920's and 1930's. For both navies the Treaty Cruisers were not well armored for ship to ship engagements because of treaty limits. Limits that the IJN didn't honor. Both navies shifted to building large Light Cruisers with twelve to fifteen 6-in guns as being more practical. The rate of fire was much higher and protection was made better than the Treaty Cruisers. The USN by the mid-1930s had only the OMAHA class in service in the light cruiser category and started to build the BROOKLYN class for the Scouting Force. However, new cruisers were still needed as replacements for the OMAHA's. The USN went through several studies and efforts to derive the "requirements" for new cruisers and settled on the CLEVELAND class and ordered them in numbers.
The CLEVELAND class was in fact basically a revised BROOKLYN class with one less triple 6-in gun turret and more 5-in DP guns, taking into account lessons learned from the war in Europe. The large number of the CLEVELAND class ordered and many built or converted to CVL's, show that the USN desired this size and type of cruiser. The rebirth of heavy cruisers in the USN with the BALTIMORE class (as well were the ALASKA class of large cruisers) was done in response to the existence of 8-in armed German "Raiders" and the IJN cruisers that were better armed and built over the treat limits to begin with, plus rumored cruisers by them with even heavier armament. They were added to the "Two-Ocean Navy" plans and didn't start seeing service until 1943. Their construction priority fell behind the need for Carriers, Destroyers, and Landing Craft.
The ATLANTA class cruisers were NOT designed and built as AA escorts. They started out as being Destroyer Leaders that were intended to add firepower to the classic torpedo attacks on the enemy of her destroyer charges. As the size of the ATLANTA class grew, it was reclassified as a LIGHT CRUISER. Many in the USN didn't really know what to do with them as the war started. At the start of WWII it had already been decided that the class would only include the eight units of the class already ordered and being built (six laid down prior to 7 December 1941). The repeat ATLANTA's (of which only three units were built arriving after the war was over) were ordered AFTER it was found that they were useful as carrier escorts as replacement for lost units. Even then, the CLEVELAND class and BALTIMORE class cruisers carried almost as many 5-in DP guns as the ATLANTA's and were much more flexible in tactical assignments than the ATLANTA's. The USN shifted to wanting AA qualified 6-in gunned cruisers instead of more ATLANTA class types.
At the time of heavy losses of the pre-WWII Treaty heavy cruisers and even BROOKLYN class cruisers in 1942 and 1943, the newer units were being delivered and working up for service. By that point the new ESSEX and CVL's (along with more capable large destroyers of the FLETCHER class) were also reaching the Pacific and whole Task Forces were being formed around them. There really were fewer opportunities for cruiser on cruiser engagements after mid-1943. Battleships were not being deployed to the Solomons battles for fear of losing them in the confined waters better suited for cruisers and destroyers. Battleships, the older units, were being deployed just outside the Solomons as a bulwark to any IJN assault beyond where they were already. Plus the newer battleships were added to the carrier task forces because of their speed, to add AA firepower. To have had more cruisers available in late 1942, the USN would have needed to have built units and "operationally" ready in the late 1930's. That just wasn't going to happen prior to the outbreak of WWII in Europe in September 1939.
: Considering war losses at beginning of war why
: so few heavy cruisers being added to the USN
: WW2 fleet? Was it resources and economy or
: doctrine and tactic change?