Because BITD most the satellites of interest, those with the subscription channels, were in the western sky. Basically 137 to 97. Very few channels were east of there.
You are wrong about this...lots of great channels east of 97 over the Atlantic. CBS/CW HD feeds on 89, Retro TV on 87, Nascar stuff on 83, MSNBC/CNBC/Weather/NBC on 72, NHK/France24 News on 58, BBC HD on 55, Bloomberg/RT on 40 and tons of Spanish stuff!