Well there is a significant caveat. When comparing how much people are paid over time, you should really use an average earnings index rather than RPI. AIUI Average earnings tends to run ahead of inflation, or at least did till about a decade ago.
Another point is that today’s chiefs are running rather more railway than their predecessors - and by that I mean more passengers, more trains and certainly a lot more investment.
Finally, whilst Andrew Haines ‘only’ runs one part of the industry, he is also running the transition to GBR, and is seen (certainly by DfT) as the defacto person in charge of the whole system.
So with the last point, similar to Bob Reid 2 who had to prepare the transition to privatisation.
It would be better if there had been a larger increase in actual railway as well !
Perhaps rail chiefs pay should be proportional with the amount of route mileage they manage. That would be a good incentive !