From S3 to R2: An economic opportunity

If I understand correctly when storing data to vanilla S3 (not their edge offering) the data live in a single zone/datacenter right? While on R2 they could potentially be replicated in tens of locations. If that is true how can Cloudflare afford the storage cost with basically the same pricing?

It is clever marketing. Your object in R2 is stored globally as in it might reside anywhere, but they do not actually replicate the object globally.

S3 Standard guarantees that your data is replicated to three availability zones within the region at minimum. (That's different data centers in the same city.)

My assumption is that "at least three" means "exactly three" in practice.