The big lie is that connection speed within the ISP means nothing. Most of the time when I experience packet loss / congestion you can clearly see it's in the connection from the ISP to other providers, and some providers are cheap you will suffer high packet loss and congestion exiting their network. The advertised speed is meaningless when 1 in every 30 packets is dropped. Just small packet loss is enough to slow TCP
Well, packet loss here really is a bandwidth problem, though. The packet loss happens because some link is saturated and packets are arriving faster than they can be transmitted, and TCP simply reacts by adjusting the sending rate so as to not exceed the available bandwidth at the bottleneck.
Still true that the problem often is more the peering than internal infrastructure, yeah.
