We (IPinfo) have a practice of adopting low-maintenance, high-utility services. Generally, we adopt websites that would have become defunct and run them as services.

Even though IANA says example.com is intended for documentation purposes and not as a service, I feel that it nonetheless serves as a service to the broader internet. I think there are some cornerstone services on the internet, regardless of the maintainers' intentions or their legal definitions.

For example, we ourselves sometimes have to recognize that we are not a standard API service. Considering that we expect to process 3 trillion requests this year, a major outage could take down a good chunk of IT systems everywhere. So, we invested in infrastructure to avoid outages. We then started adopting other cornerstone services and running them indefinitely because we might as well support the users who depend on them because we have infrastructure to support them and us.