Actually it is more like reducing the need for further investment in checked luggage infrastructure. Given the rate at which ridership is increasing, there is a lot of incentive to reduce the amount of checked baggage per passenger to handle, and I don't think any airline is feeling that they have a lot of idle capacity for checked baggage hanging around. This is a fantasy of the AU land.
Irrespective of business or otherwise, one has to be crazy to try to take the Blue Line in Chicago with a pile of baggage. The shared shuttle services (Blue Smurfs and others) are quite cost effective and much more suitable for carting around piles of baggage. Indeed, when I traveled to Chicago on business I never even remotely considered taking the Blue Line.
OTOH, in London, even on business trips, I have always taken the Piccadilly Line or the Heathrow Express/Connect, depending on what my destination is within London. The difference is that the Blue Line is just not as user friendly as the Piccadilly Line or the rail services to Heathrow.