I'd argue that S3-compatible isn't exactly what you'd need though. You'd need S3-compatible with similar latency characteristics for read and write, with four nines of availability and 10+ nines for durability. [0]. Their metrics are, quite honestly, absolutely impossible for most engineering teams and companies to ever achieve, no matter how hard they work at it. In essence, what I mean is Cursor could migrate Origin out of Amazon's S3, but they'd lose a lot of reliability and/or performance in the process.

[0]: https://aws.amazon.com/s3/ (Click on Durability and availability)