They're averaging 1,300 fewer than us:
https://www.footballwebpages.co.uk/premier-league/attendances
And yes, my brother and my best mate are Saints fan - both are just pissed off with it all, and yet their gates are similar to ours. I do think we're very similar clubs these days - similar...
The only caveat to this is that people have been underestimating demand for Albion tickets for the best part of a decade. I remember when the Amex was first mooted, the consensus was that we'd be broadly similar to Huddersfield. Then we sold 14,000 season tickets. After one season of sold out...
The simple attendance comparisons don't really work here though, as our ground is sold out pretty much every league game. Given a limitless capacity like your 48,000, we'd be averaging 10,000 more than you I suspect.
Sunderland are a big club though - I can only think of one other club...
The cost of stadium expansion would be astronomical and completely out of step with the rewards it might bring. From that point of view, it would only ever get done as part of a Tony Bloom vanity project and that doesn't seem to be how he chooses to run the club. Regardless, as Wozza says, I...