That’s not entirely true. You’re missing some logistical details. Cloudflare would have to audit ALL of their customers to see who’s running a relay in order to try to shut them down, either one-by-one or in one go. But first, they’d have to handle it legally by the country’s regulation of each customer. What legal basis would they even have to shutdown the relays in the first place? It’s just code. And the smaller providers are just leasing rack space from the bigger ones anyway lol.
I disagree with everything you said
First Cloudflare is a massive privacy risk, it's absolutely ridiculous you don't see it that way. They measure the speeds users pull data, this alone can doxx nostr users. They browser fingerprint users of websites. What does privacy even mean if they see everything?
https://simplifiedprivacy.com/why-and-what-is-arweb/arweave-website-creator.html
Second, the idea that you need millions of concurrent users is ridiclous. It's the same small bunch of people here on Nostr. Both you and I can not even get 100 reactions if we tried. Nobody cares to DDoS you, or the users using that self-host relay.
Third, there is no purpose in decentralized tools if 2-3 entities control them all. And the only solutions you mentioned are international giants or in your home. You're completely leaving out smaller providers
Let's take your logical thought to the extreme.. if everyone hosted nosflare on cloudflare, then it would be a regular social media site with a single entity. So the only thing magical about Nostr, is those who DON'T use this.
Discussion
a) Massive privacy risk. Please see the article linked above.
b) Nostr has scaling issues completely outside of how many clients can hit up 1 relay at a time. The issue is you literally can't connect to 1000s of relays, so it forces centralization as people use the same popular ones with dramatic different outcomes. Even fiatjaf admits this
c) No they don't have to "audit" each one, they can knock out the biggest popular relays in seconds, its public on clear
d) No, you're completely incorrect on the smaller ones. You have not properly researched this