FreeSpace does disperse its efforts, though, and it's really hard to disengage in FreeSpace.
First: that's not actually an obvious inference. The only time we get a real sense of the flight tempo of a GTVA destroyer is during the endgame at Capella, when they are balls to the wall and beyond any normal definition of "maximum effort". The pace of operations, based on any time we fly destroyer escort or are attempting to clear the way for a destroyer, suggests it's actually much slower as they rarely devote more than a squadron to the task. (In some ways, FS1 actually seems to have a higher operational tempo considering the scale of ops like the attack on the Eva vs. many of the FS2 missions that are similar, like The Sicilian Defense.)
WW2 ships disperse effort too; and what you're ignoring is that most of the dispersed effort, CAP and ASW patrols, always comes back. You're trying to argue for the majority of the dispersed effort suffering just as hard as strikes, as far as I can tell, which is crazy talk. If you want to talk about situations where we're in the game and which we're emulating in the missions, it's strike ops. That's the comparison being made.
Second, the argument it's very hard to disengage is ultimately fanon, and while it does match available evidence nicely to say that these people can't rather than won't disengage, I've seen more than enough fighters jump out and survive to know that what you're saying isn't a gospel truth.