OSM gives people the tools to create their own map rather than offering them a simple, out of the box solution
On this point and the main part of the first argument, I kinda disagree; the OSM project should specifically aim to do that: providing means for one to create a service.
However, providing an actual map service would cost much, much more in bandwidth and I doubt a free software project like this has that kind of funds - actually serving tiles can add up to large costs pretty fast if enough people use the service.
So if you want an actual service, you either do the hosting yourself or go see mapbox/whatever.