In my opinion, the killer feature at some point stops being throughput and becomes latency. On 80% of the web, loading a webpage will fetch 100 1kb file (I'm exaggerating), and it's way more important to have 15 ms latency to the servers serving those files than it is to have 100Mbps, 1Gbps or w/e throughput.
The fun fact is that fiber deployments are usually seriously improving latencies over copper ones which is what will get noticed when browsing casually.
So I wonder if the american congress could cheekily say "Sure, 100/20 is good enough as long as you ensure a 15ms roundtrip latency to any server located in the US...good luck with hawaii"