Last year I took a subscription to Backblaze, (incidentally) I have around 8TB of data, I have a gigabit upload (a real one), but Backblaze servers are on the other side of the planet for me. It took around 3 or 4 months to upload it all.
That's to say, there's more to it than upload speed, if Backlaze had servers in Europe I'd recommend it much more than I do.
The core data that I'd want to restore immediately if I lost my primary fileserver is only around 100GB or less
I have several TB's of other data (mostly photos, videos, etc) that I'm fine waiting for weeks or months for if needed, but if you're in a hurry, Backblaze will sell you a hard drive that they restore your backup to and mail it to you.
Then I'd need multiple hard drives for redundancy, and I have to bring them back and read them regularly to make sure the data is all readable. And while I have a large amount of data that I rarely touch, I have a small amount that changes frequently, so I need to include that data in my off-site backup too.
Or I could just sign up for a cloud backup service, spend a month or so uploading my initial snapshot of data, and then backups are automatic and always offsite, replicated, and scrubbed. For $10/month.
Most non tech savvy people don't even have that much data to backup: most of their heavy stuff (music, pictures, etc), are now attached to an online service.
Plus you only do it once. Differential backup would take down the size of the next backups to a few Gb, or even Mb.
It turns out that actual throughput on nominal "gigabit" consumer ISP connections ranges from 0-95% of the branding. It is only safe to consider them as "may burst as high as 980 Mb/s" and to actually test your connections to any given destination. Oversubscription and the resulting congestion are assumed into the consumer ISP model.
+ $400/yr for storage. A few hard drives, DVDs, and tapes are much cheaper and pretty easy (even if you have to pay $500 once to get an IT pro's help.)
HDD need regular replacements if you want them to work in 30 years. It's cheaper than 400$/year, but not as much as you might think especially if you want to ensure 3 copies of each piece of data.
Even assuming that a consumer "gigabit" connection is actually delivering that speed, you also have bottlenecks in the wire protocol (sftp or scp or https or whatever) and the storage service. It would take me longer than a day to copy 8T to the archive storage within my own data center using HSI (an ftp-like utility for accessing HPSS storage).
