"I don't know any online provider that can do a 2TB restore in any timeframe that I can work with."
There's probably a significant portion of the market that will be happy with a next gen smart phone that unfolds (or unrolls) out to A4 size and all the storage is in the cloud. Any problems and either factory reset or a new device, enter their account details and it's like nothing happened. No need to download a backup, or at least not much a data backup. Android and iOS already work in pretty much that way for a lot of users.
Personally, I prefer to be be in charge of my own data on my own local storage, but that's not how Joe Average thinks or works. At least not until one of the major cloud providers has a major, multi-day "issue"