Cannot get httpd to listen on port 80
I figured it out.

I had started another instance of httpd by mistake earlier. I typed:

httpd --help


And while httpd doesn't recognize this command (what I was looking for was httpd -h), it did start a daemon, that was listening according to the old config file.

I'm very surprised that brew services start thought it was starting the server properly (brew services list did display it as started), even though it probably wasn't running because of the conflicting instance.

This is really confusing as start/stop did toggle between "started" and "stopped", even though it probably wasn't doing anything under the hood.