But that means that bandwidth is still utilized, while a bandwidth cap at, say, 10Mbps would mean that 10 users are make up what one user at 100Mbps make up. In theory, a neighborhood or block might have the cable infrastructure to support 10Gbps simultaneously. There is no real benefit for the ISP to ensure that bandwidth is 100% utilized, so they have no incentive give a user more bandwidth than they paid for. Thus, capped bandwidth.

I’d suspect data caps are useful for over sold areas, but are great for lining the pockets of greedy ISPs.