I was including capacity to react to perturbations as part of the meaning of competition- with better competitors having more capacity to react. To you point: A highly turbulent market seems to require competitors to spend more resources reacting automatically decreasing the amount of value that a monopoly can just extract directly without endangering its own viability/market position. ..So you are right, 'market volatility' seems to be a factor that opposes some characteristics of monopolies.

I try to translate the problem into information theory so I can access those tools. In doing that, I was using a signal model as an analog of market conditions to represent the sum of the forces acting on the market. You can imagine a signal that moves around quasi-randomly, sometimes with large amplitude changes, sometimes with changes happening quickly with high frequency. An impossibly competitive and efficient player would conform to that signal exactly. The difference between the 'true' market signal and the signal that a competitor generates is a measure of how efficient that competitor is in the market and how much value they can extract. I find thinking of it this way is somewhat generative - despite the obvious difficulty of translating an actual market into this abstract form.