Wait, someone paid them for DNS before? It was many FREE DNS services since early 00's, I even will not say nothing about the domain names registrants who almost always (with literally few exceptions) provides free DNS.
Domain Registrars usually have shitty, subpar DNS eg. without Anycast or DNSSEC.
Amazon Route 53 is $0.40 per million DNS queries - which would terrify me if I used it, considering a typical 10Gbit server connection hosted at a unscrupulous ASN with no egress IP filtering is capable of sending a million DNS requests per second from random spoofed IP addresses.
Uh, paying for DNS isn't uncommon? Examples off the top of my head:
- Akamai DNS
- AWS Route 53
- Azure DNS
- Cloudflare (excluding personal/hobbyist plan)
- Google Cloud DNS
And many, many others. And I note the site you posted this comment on is using Route 53, so probably paid as I doubt their query volume would be in the free tier.
Paying for DNS for personal/hobby stuff is probably pretty uncommon, because like you say, most domain registrars will offer it for free. But commercial websites often will, particularly larger ones with serious traffic.