I agree that the main challenge is to get the developer workflows right and being prescrptive here often should not be a problem from the developers' perspective.
And yes, it would be great to generally hear more about failures but naturally people are less willing to share these stories, I guess.
I see your point. The problem with exact numbers is that they are hardly (publicly) available as on the one side, there is the cost of building and running the platform, and on the other, there is potentially lost productivity (which is generally hard to measure). So, for the 2-year development example, I could only rely on the KubeCon talk, and it just mentions costs briefly (saying that it was cheaper for dev teams to use the platform).
Another problem is that it can be very different depending on your situation: If you are currently working with local clusters that are free to use, the direct cost benefits will be much lower than if you use individual clusters for each developer, which are quite expensive even for small teams.
So, I just wanted to give a rough overview of what that drives cost and where you potentially could save money.
The cloud providers more or less just give you a Kubernetes cluster. You can then connect this cluster (or any other cluster in a private cloud) to DevSpace Cloud, which allows developers to create their own namespaces on demand in the cluster.
DevSpace CLI is supposed to enable developers to work with Kubernetes regardless of their experience in working with k8s.
Overall, DevSpace does not replace the cloud providers but makes their Kubernetes offer accessible (DevSpace Cloud) and easy to use (DevSpace CLI) for developers.