There is sense in that we would be paying (presumably) half the cost to move from a stadium that is perfectly adequate for our current needs, is in a reasonable state of repair, and has enough land for us to expand if we wanted to, into a soulless bowl that we have to share with them lot.
Those are just the reasons we shouldn`t leave BDTBL.
Then, look at the other side - we'd be giving a huge leg up to our direct rivals, who would also pay half the cost to move from a stadium that is a complete shit tip, is built on a flood plain. That stadium is currently a millstone around their neck. Let it drag them down...
Why give them (or help give them) a get out of jail free card?