This link here takes you to a house show report on the Observer for 12.05.2004 Smackdown house show at Madison Square Garden. Pay close attention to the first line of the report where it shows the attendance. Isn't there something a little... odd about that, considering it's an MSG show?
6,000 to 6,500 for a Sunday afternoon house show isn't an awful figure in the current marketplace. This isn't the old days of MSG where the McMahon's would bang the place out with 22,000 plus every month. If they were doing that, they would book MSG every month for a house show, rather than just once every six months.
Cena's great - his whole gimmic is so fresh and he does it so well, connecting with the crowd. Plus he's intense and isn't bad in the ring... definitely could be a main eventer making WWE lots of money in the near future if they play their cards right.