It's compelling to you, but managing email infrastructure is a huge burden - users actively spamming, compromised users spamming, RBLs, security, myriad email clients - there seems to be little synergy here with the rest of Cloudflare's infrastructure (DNS + a big proxy stack).

I say this as both someone who worked at a hosting company doing managed email a long time ago, before the industry had consolidated to the extent it has now, and as an ex-employee.

At wholesale registrar pricing, N real inboxes - is that attracting the right kind of users at scale? At least with their current freemium + addons model, it's fairly hands-off, with the hopes of capturing rapidly growing startups in the process. I don't think you can replicate that with email at all.