This is true. While I prefer non-SaaS solutions generally, S3 is something that’s hard to cost effectively replace. I can setup an AWS account, create an S3 bucket, and have a system that can then persist at least one copy of my data to at least two data centers each within a goal of 1 second. And then layer cross-region replication if I need.

It’s by no means impossible to do that yourself, but it costs a lot more in time and upfront expense.