Cable doesn't go 1M up either. I, personally, do not know anyone with an actual, functional 1M up. And this includes a 1M up business cable connection -- TW can and will drop packets above 500k, the best I have ever seen it do is ~900k.
I call BS. My home line gets 1 up 15 down consistently. my 2 up 15 down business cable gets that consistently. My 5Mbit and 3 Mbit fiber links get a bit over that consistently. All TW provided.