I can respect that the board wants concrete information so they can make an informed decision. That's their job.
I suggest looking to that 1975 code edition and seeing what it says. I know there are people on here who have it. Maybe if you start another thread titled "1975 NEC Working Space Requirements" and then in the body of the thread ask "Does anyone know what requirements existed for clear working space and egress from MCC in the 1975 NEC?" If it turns out a violation exists, you can provide that concrete information to your higher ups. An adverse event due to not making the correction could well cost in excess of $2MM and you would still have the problem.
Let's think outside the box though. You say $2MM and I'm sure that's just a rough budgetary estimate subject to more refined estimating and bidding. But you likely have one solution in mind. Options include moving the MCC or moving the pump infrastructure. That room has 4 walls, a floor and a ceiling. That gives a choice of 6 directions to go. Either making the room bigger or moving equipment to another room are options. There is certainly considerable cost involved but just make sure you consider all possibilities including the not so obvious.
Good luck!