Exactly. Thats the problem.eoininho said:although possible it would be very costly and it is estimated it would take 30-40 years (assuming it fills each game!) to be a viable investment... therefore unlikely!!
No doubt it would be a great investment, in terms of us having the biggest and best (although it is currently the best anyway, imo) stadium in England, and that more fans would be able to see Utd in action.
However as a financial investment, as you said, 30-40 years to be viable?
I think that line (^) is the reason it hasn't and probably won't be happening for a long, long time.