Yea for real world speeds like that you need fiber, cable can do it downstream now and has to potential with upstream channel bonding to do it up as well.
Cable is unlikely to ever see symmetrical speeds or anything close to it. In theory you could do a lot better but the existing legacy services already in use to deliver TV services get in the way. Way down the road when cable providers finally migrate to an IPTV based platform and get rid of digital cable they could do things properly. But that is so far out.