Ultimately, one can quite easily extrapolate that the reason why CSAR (and indeed, long distance special operations missions) is viable is the part of having "dozens of warplanes" providing localized overwhelming ISR and interdiction of adversary movement and troops, as well as suppressing any remaining local air defenses, to the extent that a temporary bubbles of safety/sanctuary can be created.
It's why this sort of thing generally can't be done against an adversary with a functioning air force and networked IADS -- air control (even if transient) offers localized advantages in ISR, fires, and even logistics.