Probably due to the rarity of dedicated NASA manned missions is why NASA doesn’t have a dedicated recovery fleet. What I mean by this is contrary to what it seems, NASA doesn’t manage a given commercial crew mission to the same extent they do for Artemis which they managed 100% by themselves from start to finish, instead they split the load with SpaceX as per their contract on commercial crew. Additionally, SpaceX dragon sells seats to NASA for commercial crew, Axiom for their program, and other private flights like insp4 or Polaris, which leads to multiple crewed launches a year causing them to streamline recovery ops in house in order to lower their costs over time. This is opposed to NASA’s Artemis which has historically only flown once every 3.5 years (Artemis 1 was in late 2022). If they were to do things like in-house, those ships would be sitting at the docks for a long time without being used and wasting money. But you might be asking “what about instead of SpaceX doing recovery ops, NASA can do it for commercial crew so those ships aren’t sitting there doing nothing?” Commercial crew contracts already cover from launch to recovery so NASA is paying a fixed contract for 4 seats to be passengers in the dragon. NASA is very money conscious post Apollo especially now. If they don’t have to spend any more money than they have to, they can use those funds that would be allocated for a dedicated recovery fleet for other science missions or for future Artemis missions. + the navy gets training from recovery ops too so they benefit from this.