I honestly can see where you are coming from but I think there is something in looking at what are rivals have.
The size of the stadium is often used as a factor in the size of a club, hence why lots of people think Newcastle is a massive club despite having won nothing for years and they yo-yo between divisions. Unless you have other qualities as a club - take Juve/Chelsea for example who have recently won trophies and are (usually) in the CL, why wouldn't a player take in to account the size of the stadium as a gauge to the size of the club? Why do you think Spurs settled on 61k instead of 60k if this is all meaningless?
Tbh I don't mind if our stadium is a bit smaller than the rest of our rivals but it should be a figure within a couple of thousand of the rest. If we have a 50k capacity stadium it means Spurs/Wham/RS (after further expansion) etc. will have 10-12k more than us that's a big jump especially for us that can remember that Arsenal had 38k, Utd 44k, spurs 36k, RS 42k, Villa and City around the 40k mark with us.
Do you see how we are being left behind? The people who say we can't fill a big stadium are the people that are forgetting that Everton Football Club are one of the biggest in the country, we've had years of miss management that has got everyone thinking we are bloody Tranmere. It might not be full every game but it still will be full enough.