I don't think 30,000 is that big a crowd for a fanbase like ours. Having had a quick look, of all the similar sized clubs, - Villa, Chelsea, Newcastle, Tottenham, Man City, you have to go back to the mid to late 90's when any of them averaged less than 30,000 in a season. For us it was 1994. West Ham and Sunderland have more recently but both have had fairly regular spells in the lower tier in the past 20 years.
http://www.european-football-statistics.co.uk/england.htm
From looking at that, we were around the 33,000 mark before the arrival of Moyes and the improvement in league position under him boosted our crowds more consistently to the 35,000-38,000 range. In 2012, we went down to 33,000 again, and the introduction of Martinez brought it back up once again. There has been a lot of hope in the past 2 seasons going in to the season, but unfortunately the manager didn't perform. We've now got Moshiri and a bright future ahead and I expect us to stay around the 37,000-38,000 mark next season.
We need a bigger ground though. Obstructed views prevent us from selling out more often.