Debating exactly how many data centers one needs to be "edge" instead of "cloud" is pretty silly. Ask what latency you need between your software and the customer, and then ask what providers can supply that.

(Of course, AWS egress transfer rates may be too costly, but that's not about "edge". https://blog.cloudflare.com/aws-egregious-egress/)

For an average site, that just wants basic CDN facilities (cache assets; maybe do some rule processing to control cache of "dynamic" pages etc) there are dozens.

The issue comes in a few of the niche uses.

A client of mine has been using CF for the public site for several years, but until recently used S3 + Cloudfront for content that users download (essentially purchased digital files). That content is now also served via Cloudflare, using tokens (similar to pre-signed URLs for Cloudfront, so the cache can validate that a user should have access to a file).

CF don't cache all the downloadable content (anything over 512MB is excluded from caching unless you pay for Enterpri$e level plan) but they also don't have per-{m,g,t}byte transfer pricing either.

This is obviously not a problem for a lot of use-cases, but for anyone offering downloadable content, or large volumes of network traffic, it's going to be hard to find a CDN that can compete on price with Cloudflare.