Like Mukremin pointed out, the Chicago mob got hit hard by the feds in the 80's and 90's, much like the New York families and others. But even a city like Chicago doesn't have the recruiting pool that New York does. Not that they necessarily need one at this point, since the Outfit seems to have wanted to downsize itself and streamline its operations so as to have a lower profile and less of a target for law enforcement. Traditionally at least, the Outfit was thought to have had a relatively big ratio of associates. That may or may not still be the case.

Average estimates for the modern day Outfit put it at about 50 members, which is comparable to other small families like New England, New Jersey, and Philadelphia. Gambling (specifically sports betting and video poker machines) are their bread and butter. And they are still involved in other rackets like loansharking, extortion, fencing stolen goods, etc. Even to this day not a whole lot of involvement in the drug trade by the Chicago mob. There is still some mob-connected political and police corruption though not at the level many still believe there to be. Still some labor union racketeering but much less so than in the past. Still bid-rigging for city contracts. Many of the guys in the upper levels of the organization have legitimate interests in things like real estate, trucking companies, restaurants, strip clubs, etc.

Here is some good articles that sum things up about the current state of the Chicago Outfit -

http://www.ipsn.org/characters/new_outfit.htm
http://www.laborers.org/ChicagoMag_Moblite_12_00.htm
http://www.americanmafia.com/Cities/chicago.html
http://www.thechicagosyndicate.com/2005/04/prosecutors-boast-of-hit-on-mob.html
http://www.thelaborers.net/newspapers/chicago_tribune/crackdown_just_latest_hit_on_mob.htm