I was going to mention this too. However, to be fair to the parent commenter, Apple Maps on the web is only a recent development, it lacks a ton of the features of Google Maps on the web, and its world-wide coverage isn’t great. There’s also the fact that there’s no direct web interface for it, so if you were going to tell someone using a browser to “just use Apple Maps”, they would have to jump through some mental hoops to find a way to do that.
All that said, I’m optimistic and hope they move in that direction.
It looks like their only price tier is "free with your Apple Developer subscription" or "contact us"—I wonder if their terms allow you to use it with e.g. Mapbox GL JS 1, which is much better than MapKit JS.
Where? I went to https://www.apple.com/maps/ and clicked "Open Maps" but that just brings me straight back to that same page with no map in sight, just a lot of pictures of idevices.
All that said, I’m optimistic and hope they move in that direction.