Agree that we can't begrudge a guy for leaving after 10 years.
As an organisation I cannot believe that we're so poorly run that we'd let ourselves be so exposed to key person risk. I'm certain that we would have recognised the value of Edwards and done everything we can to download his capability to his successor and to the systems we already have in place.
Obviously it would be better if he could stay, but if our whole model of operations succeeds or fails on the basis of one albeit fairly brilliant DoF, and he's in fact, irreplaceable, I'd be fairly stunned.