I suspect the 'funding' and 'equipment onboard and costs of replacement to keep it in service' would be more telling - you could standardize fighter maintenance equipment to a great degree, but you'll still need newer gear to maintain modern fighters. Ditto communications gear, ditto engines, ditto power for shielding and all those other good things.
A lot of the Kilrathi-war era ships, those which survived the war, are damaged to some degree, having been patched and thrown back out there. Quite a few of these were very old vessels slated for decomissioning before being put onto the front lines as losses of modern ships near the war's end forced Confed to plug the gaps with them.
The fleet probably suffered a LOT of attrition during the Reduction in Force, which would've shelved the oldest and most-damaged carriers first, starting with the expensive-to-maintain heavy fleet carriers. Escorts would have had fewer decomissionings, mostly because those who had survived the war may either be in better shape - or were cheaper to crew and maintain, given their lack of weapons and other systems compared to the heavy carriers.
Now in the age of the Midway-class megacarrier deployment, some of these older ships are probably going away too as newer construction comes online. The older light fleet carriers are probably going or gone, replaced by more modern designs of CVEs or any new concepts in light carriers - the problem being that most of the light carriers we saw were either pre-war or slapdash designs like Tarawa. The more modern designs, like the TCS Eagle, are probably around because of their low cost and easy deployability, though they may not have the guns an older-style light carrier had, at least in comparison.
Besides, one of the lessons that Confed learned during the Kilrathi War was that carriers -do- matter, and heavy carriers are more effective than the light carriers tend to be. The pre-war emphasis on light carriers seemed to be based on the idea that fighters were only good for ground missions and light strike and recon, rather than being ship-killers in their own right. The post-war fleet has recognized the need for a fighter-heavy fleet, given their versatility as compared to the pre-war battleships or even wartime-era dreadnoughts, especially as cheaper destroyers can carry nasty weapons of their own while torpedoes are always useful. The presence of the huge plasma cannon on Nephilim ships must've come as a nasty surprise.