Maybe because the 757 mostly flies to Europe and Hawaii and you cannot pick up wifi overwater .
Maybe US Airways should have gone with Row 44:
Row 44 offers commercial airlines—anywhere in the world—the most robust and scalable satellite-based in-flight broadband platform.
Go-GO: [background=rgb(151, 210, 236)] Gogo’s Air-To-Ground network, a reliable network of cellular towers spanning from sea to shining sea.[/background]
[background=rgb(151, 210, 236)]So GO GO is limited to where the CELL PHONE TOWERS are located. [/background]