It's hard to convince people who go along with that "but you don't really have backups, you need to download everything locally and pay $5/month".
Code is all on GitHub, all my docs and emails are in gsuite (and don't get backed up anyway by BB). The only thing that does get backed up is a load of cruft and junk I've accumulated which is actually nice to start over on tbh.
I imagine more and more people are like this. Designers who used to have to be meticulous at backing up their source files now all work in Figma, etc etc.
The major weakness now is if GH or Gsuite had a catastrophic error (or your account gets booted off for incorrect reasons). I actually think that is the more pressing backup need than local files for many.
Can you go into why Google Drive is a better alternative? I can see 2 TB for $100/yr, but I don't think the products are exactly the same.
At least with Google Drive, the 2TB plan you can store what you want and access it in the cloud like a regular file. It works with rclone and restic, so you can use it for regular backups as well and it is extremely fast. I can upload over 750GB per day in about 3 hours with Google Drive, but it would take over 3 days with Backblaze.