A simple sentence to which there is a rather complex answer…
The problem is that after the end of WWII, everyone was convinced that the next conflict would be at a strategic level using nuclear bombs…
The Korean War, however, showed the smarter ones that it won’t be like that…
So the CAS aircraft in Korea were these:
North Korea
_ ilyushin-10, Tupolev-2, Yak-18, Po-2 …
United Nations
_Corsair F4U-4B, -4P, -5N, -5NL
_Hawker Sea Fury
The greatest fame was taken away by the MiG-15 vs. F-86 and B-29 bombers,
behind them in the role of fighter-bombers were the F-80, F-84, F9F, Meteor F-8,
A-26 light bombers,
night fighters F-82, F-7F, F3D-2
reconnaissance and F2H-2 escort etc…
The Americans first tried to make an aircraft for direct CAS targeting, it was the AD-2/4 series aircraft, but it quickly became obsolete, so the next attempt was the A-4B and its next version, but it still wasn’t the same… Only the A-10 succeeded , but it is very busy even after years of quality service, in general there is a group of people in the USAF who promote the F-35 as an all-purpose aircraft, that it will be an absolute game charger in the field of any air combat, but there is also a strong group of those who they claim that the A-10 is irreplaceable and the F-35 is for CAS, too expensive a toy and definitely not a recipe for everything…
As for the Soviets/Russians, they tried different jet-bis variants for CAS, then tried to do CAS with SU-7/17/22 variants until they got to the Su-25/39…
What will be the future of CAS aircraft is uncertain, helicopters are probably over in this role, it looks like drones, either controlled from ground bases, or a flying control center of Airbus A-400M drone operators…