Large commercial aircraft have the aerodynamics of a “large” brick when compared to a smaller aircraft such as the old F-4 Phantom or even worse F-111.
Glide ratios for various airliners:
Boeing B707-320 19.4
Boeing 767-200 19.0
Douglas DC-8 17.9
Boeing 747-100 17.7
Douglas DC-10 17.7
Airbus A320 17.0
Lockeed Tristar L1011 17.0
Douglas DC-9 (1966) 16.5
Boeing B727-200 16.4
Douglas DC-3 14.7
And you still they they are bricks?