Putting aside any issues around whether clubs want RL played during the season (loads of football clubs allow it when we try), the numbers of moving to a lower capacity ground may not be as challenging as some think.
This is fag packet stuff as we don't know the exact numbers, but let's say the average income per ticker is £40, to move from an average of 70k to one of 56k would mean we'd have to replace c£560k of income, which is a tenner a ticket. Considering you'd have a little more scarcity, you'd have a better stadium, and more likely more sellouts leading to a better perception of the event, we should be confident of adding a tenner to the ticket.
It's pretty standard to be at Old Trafford and have loads of corporate boxes empty, so I doubt there'd be an issue there.
As much as I like the actual bowl for the game at Old Trafford, I do think we put up with too many negatives now - poor area, below average facilities, small pitch, poor technology etc. I don't think these things are worth continuing to put up with for history and atmosphere. I think it, and our Grand Final is looking dated now.