I wonder how many generations of ransomware we will see before backups come back into "style". It used to be in the '90s that people actively did some type of backups, and even PCs shipped with some form of tape drive. Then disks got cheap, and offsite storage become viable, so backups were not done, or if done, were just kicked to the cloud.
Any backup is better than none, but I wouldn't be surprised if the next generation of ransomware would either encrypt files slowly (but use a shim driver to decrypt stuff until it is done, and then completely zap all decryption keys and tell the user to pay up), or if it does notice a backup program being run, actively or passively corrupt it... or just erase the hard disk or the file share it is being backed up to. A simple TRIM command would make the data on a SSD unrecoverable. An overwrite of a directory synced with a cloud service will make that unrecoverable.
I wouldn't mind seeing tape come back, as it isn't slow, and it is relatively cheap (I've seen ads for LTO-6 tapes for $10 each.) The drives are pricy , but tapes are reliable , LTO4 and newer have AES-256 encryption in hardware (and very easy to turn on, be it by third party software, the tape silo's web page, or the backup utility.) A tape sitting on a shelf takes zero energy to store (other than HVAC), and if dropped, unless there is major physical damage, it is almost certain the media will be usable.
Will tape be 100% against malware? Nope. However, it keeps the data offline, so that a single "erase everything" command won't touch the data . One can buy WORM tapes to protect against erasure/tampering as well, as well as flip a write protect tab.
In a ransomware scenario, WORM tapes would be very useful, especially if the malware decides to try to force an erase on all backups. The fact that tapes tend to be offline brings even more security since if the tape isn't physically in the drive, it can't be touched. Again, nothing is 100%, but the barrier for ransomware to destroy all backups goes a lot higher with offline media than with cloud storage or an external HDD.
I wouldn't mind seeing backups be done again, and done in a smart, time-tested way... done to local, archival grade media that is very inexpensive, but yet super reliable.
: I think there is a market niche for USB3 tape drives at the consumer level. Newer drives have variable speeds to minimize/prevent "shoe-shining", and with all the space on a tape, if areal densities similar to HDD are present, it would store quite a lot of data, even with multiple layers of forward-ECC. LTO tape drives are even bootable so a bare metal restore can be done with just the tape in hand and the drive on the machine, no other media.
: In the past decade at multiple IT shops, I've gone through thousands, possibly tens of thousands of LTO tapes. The total number of tapes that I introduced to the degausser were fewer than five, and all the errors thrown when read/written were all soft errors, so all data was recoverable. This is pure anecdotal evidence, but it has impressed me personally on the reliability of these drives. It is wise to have a backup process of rotating tapes and having some task just verify data when nothing else is going on, and goes without saying to use multiple media just in case hard read errors do happen.
: One can tell a tape silo to zero out all tapes sitting in it, but that is going to take some time, and not be instant. It can be done... but if one has a basic offsite procedure in place (where all tapes leaving get the write protect tab sent), even this can be mitigated without much time and effort.