I think the last time, the issue was that it could potentially take years to build a new stadium and they'd be stuck in the meantime with a capacity of 36K. That was totally inadequate for demand at the time, on the back of the excitement of the first Keegan era and, after a blip, with Sir Bobby Robson continuing to earn European football regularly.
My impression was that the fans would have tolerated a move if the new venue was good enough, but not if it was just a bigger version of one of those flat-pack out-of-town bowls that were very common in the late 1990s and early 2000s. I expect it would be the same now - a good enough venue, and they'd accept it, which won't be a problem under the Saudis. They'll want anything they build to be truly iconic.
I see above that the suggestion is put forward that they could, using modern techniques, expand to 60K or more where they currently are. I don't for a minute exclude that option. However, my suspicion is that they'd prefer a state-of-the-art new build where they can set capacity according to their own wishes and have freedom to extensively develop the surrounding land. I may well of course be wrong.
