Seems overly cautious to me, given the inherent cost and disruption contained within expanding a stadium.
This modern and unhealthy obsession with filling a stadium every week, caused principally by social media, is a blight on the game caused by people with micro-penises who rarely go to games themselves. Sad cunts.
It's surely better to have a 60k stadium that's 80% full half the time and 100% full the rest, than a 52k stadium that's full every week.
It's akin to not building an extension on a restaurant that's full every weekend because you're worried that it will be half empty on a Monday and Tuesday night.