No object lock API would help you if the business where you rent the service is going out of... business. With all your data - and you are without.
replyOr even fancier - just changing the price for the egress.
That only matters if it happens literally at the same time as a failure of your primary storage. If they increase the price you can just close your account and move the backup to another service.
replyThe probability of a hard drive failure or ransomware at the same time as backblaze or aws going out of business is pretty much not worth thinking about.
The probability of an attacker using the api key in your backup script to destroy the backups is far more possible.