AWS has zero interest in S3’s API being a universal standard for blob storage and you can tell from its design. What happens in practice is that everybody (including R2) implements some subset of the S3 API, so everyone ends up with a jagged API surface where developers can use a standard API library but then have to refer to docs of each S3-compatible vendor to see figure out whether the subset of the S3 API you need will be compatible with different vendors.
This makes it harder than it needs to be to make vendor-agnostic open source projects that are backed by blob storage, which would otherwise be an excellent lowest-common-denominator storage option.
Blob storage is the most underused cloud tech IMHO largely because of the lack of a standard blob storage API. Cloudflare is in the rare position where you have a fantastic S3 alternative that people love, and you would be doing the industry a huge service by standardizing the API.