A new build would cost, based roughly on the City model ( GBP 2300 per seat at the time ) eg not London priced and with a bit added on for inflation would be about GBP 2800 per seat
= 140M for 50K seats
paid over how many years 20, 25, 30?
+Interest
Phased Redevelopment will be a lot cheaper, still over 15 -20 yrs, but with a sort of 'pay as you go' method of 15M here 20M there would suit our more modest means
Maybe unrelated but, since The Emirates and the loss of Henry Viera and others and the seeming reluctance to pay big big money appears to have resulted in a for them a drop in standards... from 1 / 2 to 3 / 4... not a lot I know but significant... a loss we could not, from a playing point of view easily carry.