Nonsense. One order of magnitude more, at most. On-line storage costs are on the order of $100 per TB per year.
I was going based on my experience with AWS, which is about $30 per TB per month for spinning storage, or $360 per TB per year. An 8 TB hard drive should typically last you about five years, and costs about $250, or about $6.25 per terabyte per year. That isn't quite two orders of magnitude, but it is pretty close. Of course if you're willing to wait several hours to start getting your data back, you can use glacier storage, and that's cheaper, but there are tradeoffs.
Upload time sucks, but only for the initial upload, which I did two years ago. After that, incremental additions are pretty negligible.
Must be nice. I backed up over 12 GB Sunday night, and that was only one week worth of incremental backups for my personal laptop. Over my DSL connection (soon to be retired), that would have taken two days. It would take several hours even over my new cable modem service. It took five minutes to back up locally. That time difference makes the difference between me being willing to back up regularly and never backing up.
Obviously, YMMV, but I would imagine that somebody with multiple terabytes of personal data is probably either a photographer or videographer, and therefore has the same sorts of nightmare backups that I do. But I'm just guessing here. For all I know, it could be a porn collection.