I have internet at home through Comcast, a huge and universally hated ISP in the USA. I also run a home server (though it only takes incoming connections, and does not visit websites itself). I purchased a dynamic DNS service that would update my domain's DNS whenever my home internet's public IP changed.

In over 5 years and through numerous modem reboots, my IP address has not changed once. A year ago I transferred my domain to another provider; I did not bother setting up dynamic DNS again and my website still works fine.

I have not purchased a static IP from Comcast. When I initially set up the server I had read that my home's IP address can change anytime the modem reboots, or possibly anytime at all, to any IP in Comcast's pool - which is why I subscribed to dynamic DNS.

So a static IP may not be as unusual of a setup as you say it is.

(Edit: I mean that the static IP was almost always included by default in the standard setup, I didn’t have to request or purchase one)