The good part is you are a customer of AT&T, one of the major players in the industry. That means your place and cloud storage companies on the Internet are well connected and should have decent speeds.
On the other hand, ISPs oversell their bandwidth, especially on residential services, either to save cost or to subsidize their business services. That means you are sharing the 1Gbps with your neighbors, even you might be noticing it.
On the cloud storage providers, it's pretty much the same. They don't have 1 Gbps dedicated just for one customer.
So your option would be not only building your own cloud storage, but also pay much higher prices to remove the bottlenecks, if you really want to saturate the 1 Gbps.