It's very unlikely for all of your disks to fail at the same time. Even if they do, that's why you have an offsite backup. The name of the game is redundancy, not longevity.
In practically every use case, two consumer disks will be better than one enterprise disk. Once you start failing enough disks often enough, longevity can be worth the additional cost. Until then, it just isn't.
Actually, it's not uncommon for a batch of disk from a vendor (the same lot #) to have failures.
And again, a backup is fine for deleted data, or fire/ransomware. But for day to day operations, no one is really willing to wait for you to restore from a local backup, much less an offsite backup.
I think if you had worked/managed a SAN, you might realize that a single disk failure is a non-event. I'm not talking about a JBOD or an storage shelf using RAID5, I'm talking about a Netapp or similar system that can easily handle disk failures without interrupting service.
All disks fail eventually. Outliers may run longer than the MTBF for that drive model, but they all fail eventually.
And backups are fine for restoring data, but they don't help provide access to that data in a timely fashion. That's why people use SANs, AWS etc.
The cost of a SAN storage array is a nit for a business making cars (like Toyota) or selling insurance (like my company).