Er... I don't think 300 dwellings is anywhere near real capacity.
In the UK, cable is delivered with DOCSIS (Actually EuroDOCSIS, same thing, slightly different frequencies), and it's by street, and our streets are much smaller than the typical US "block".
It might be 10Gb over, say, 30 dwellings, or one apartment block. But the bottleneck will ALWAYS be the uplink anyway. What would you need to put 10Gb from multiple clients back to the net? Are you honestly expecting some 1Pb connection at Comcast somewhere? Highly doubtful. Caching, proxying, and the fact that people consume in small bursts or little dribbles whatever they are doing (gaming, web browsing, emailing, downloading, etc.). That's why P2P is such a pain - nothing to do with the legality, entirely to do with the fact that you can max out the uplink connections with just a handful of users.
But that's the same wherever you are. Even on, say, a workplace or school network, your uplink probably isn't on a pair with your between-server connections, and certainly only an order of magnitude better than your client connections at best (e.g. 100Mbps to hundreds of clients, 1Gb actual upstream, or 1Gb/10Gb, etc.).
But, still, a 10Gbit connection will download files, reduce latency, browse the web 10 times faster than a 1Gbit. You won't be able to max it out 24/7, that's all. Nothing's changed in that respect in decades.
Hint: When you upgrade your home network from Gigabit to 10Gb, you will need to multiply everything above it by 10 too or you'll get worse performance than before. Please tell me where you're going to buy 1Tbps kit from (even as an ISP) that isn't so prohibitively expensive that you can only afford to do it on major links and not every 100 clients.
We've just about got 1Gbps as "mainstream". 10Gbps is still expensive but is commercially available to all. 100Gbps is a pipe-dream unless you're a datacentre or ISP or huge enterprise.