Why senior officers might stay and argue within government

Why are senior British officers not resigning over the problems facing their services?

Staying preserves their ability to press the case internally if resignation would have little effect and could produce a weaker advocate as their replacement.

Senior officers have a responsibility to explain their service's needs, while political leaders make the final decisions. The argument against resignation here assumes that the government would absorb the political damage without changing course. Remaining in post would preserve an officer's ability to argue within the system. Resignation could instead bring in a successor less willing or less able to challenge those decisions. This is a judgment about the circumstances discussed, rather than a rule that officers should always remain.