They used to: CloudFlare becomes Cloudflare (2016), https://archive.is/v1C1H
- You can't serve all kinds of traffic with Cloudflare self-serve plans. Including some of the ones that tend to use the most bandwidth.
- According to the CloudFlare self-serve plan TOS, IIRC, if you start being a too-heavy user on the those plans CloudFlare can (and, I've heard, will) tell you to upgrade to an enterprise plan. Last I checked (this part's personal experience) they're not super interested in serving enterprise customers very far under a minimum $5k/month level, so there's a huge gap there in which other services are a much, much better value.
But I guess nobody's really pushing traffic so nobody cares about $/GB.
Their pricing's insane in a world where you can get prices not too far from that wholesale rate for CDN service (which is a whole different beast from having one or two colo'd servers).
And anyway, nobody pushing serious bits is paying public rates, anywhere. Those discounts can be huge. In fact I wouldn't be surprised if part of the reason cloud providers have such high rates is so they can give their counterparts an easy, very impressive-looking "win" in negotiations.
This applies to all "enterprise software" too, btw. We've had quotes from vendors that started at 50% off list price, and then negotiated down further from there. It's pretty ridiculous.