Cloudflare isn't even that big. They're 1/100th the size of Google or MS. They're not even the biggest CDN—Akamai has twice the revenue, but it depends on what you measure. Cloudflare gets brought up disproportionately often on HN because they have generous free tiers and cater to indie hackers more. So it feels a little ironic that they're perceived as "the big dog" by the indie hackers.

It feels like every website uses them as a web proxy, meaning they get to 1) decide which users can access the site using their own opaque methodology and 2) MITM/inspect a large percentage of web traffic.

I think spreading out between them is a good strategy. Cloudflare has been flawless for me for email.