[kayoone]

I guess you are mainly referring to DSL internet connections because this is not a problem for cable providers. They might have some problems inside their network at times, but in theory you CAN get the maximum bandwidth. For DSL it heavily depends on the distance to the next access point and therefor is pretty much impossible for ISPs to predict and the reason why you see all of these "up to 16Mbps" ads when in fact all you can get is <6 because of the distance to the AP.