GM is useless structure, it’s already crumbling, that reality means it will cost an absolute fortune to renovate up to a modern standard. I doubt it’s even possible without massively altering the appearance of the stadium and its structure, the whole thing the authorities have done everything in their power to prevent.
Additionally owning a protected building is a massive problem and hindrance as it binds you with incredibly restrictive legislation that binds you on hands and feet in what can be done.
But the stadium needs to be handed over for free or else it’s not an attractive offer. I also doubt any owner is stupid enough to accept any deal that doesn’t involve full ownership.
I’m really only for moving, the clubs future is more important than a structure that you can’t keep alive for ever under any circumstances, it’s just a matter of time before the structure would not live up to safety protocols and no sort of renovation is going to change that.