actually it is becuae you dont understand how tv over IP or dsl works you only stream the channel your watching and the boxes only can do up to 3 tv's at the current box from motorola fyi and that isnt HD/...
You are right, it is not HD signal. I work for a telco offering DSL TV, and High speed. the TV requires 3mbps, and we offer 1.5 mbps internet. @ 25mbps, we could in theory run 7 TVs, and still give a 5mbps connection. The number of TV's drops when you add HD, as it obviously uses more bandwidth.