So, the way I look at it (paradoxical as it sounds): If somebody is not replaceable (and hence a potential bottleneck), they are by definition a risk. Therefor

So, the way I look at it (paradoxical as it sounds): If somebody is not replaceable (and hence a potential bottleneck), they are by definition a risk. Therefore, it is in everyone's best interest to replace them and the system that enabled them, in order to harden everything against bad luck. The cowboy coder who wrote most of the MVP in PHP in a month, for example, should be replaced forthwith if she can't document her work and get the rest of the team up to speed--if for no other reason than that she is a liability as the team grows and more things depend on her not failing. It's kind of a counter-intuitive way of looking at it, but it makes sense.