I don't think tickets should be that difficult to get - we haven't broken 30k at a Mets weeknighter (Monday-Thursday) at Nats Park since 2008 (best we've done since then under such circumstances is 23,944 on Wednesday 29th September 2009, and that was our home finale).
Rather a change from the way things used to be - remember back in RFK days when it was the Mets, not the Phillies, who used to pack out our home matches with opposition fans? The Phillies didn't really become a scourge till after they won the Series in 2008.