Dealers' Den at Anthrocon... there are several pros and cons to that huge spread of offerings, like a flea market.
The sheer number of vendors increases the revenue generated, but dilutes the revenue garnered by individual vendors that will, in time, bring them to question the value of securing a table.
It does, however, increase the potential rate that auctions at the art show bring them.
Most artists severely restrict their commissions, as they must lest they become swamped and unable to actually enjoy the con for what it is rather than just another day hitting the clock, while they are more open at the smaller regional cons.

Unfortunately they have to balance how many of the regionals they can attend leaving many out in the cold. Particularly those such as TFF, despite its growing attendance (1500 this year), because they usually focus on MFM as their 'midwest' stop. Others like TFF (Texas Furry Fiesta), Oaklacon, and other south/central cons are left hanging by many.
Though that does decrease the dilution factor for those that do attend.