> it sure shouldn't cost less to do it yourself.

This is an interesting point and something I often wonder about. I think there's a number of different reasons for it, obviously markup and the need to make a profit, but one thing I realized is that when you buy something like AWS, you're often paying for the platinum version, with redundant power, networking, etc, and not the bronze version, which a lot of people would settle for. If I setup my one single instance Grafana VM or physical server, it's going to be a lot less expensive than a solution that's both multiple layers of "platinum" and multiple layers of "markup"

Datadog probably runs on the cloud, which means you get the cloud markup and datadog's mark up both built in.