Open source business models

> It seems to me that a model where the source and periodic builds are available for free download for self-supported self-hosted software works reasonably well for projects like Proxmox and Ubuntu.
> Customers who need official support, customizations, SLAs and/or hosted solutions purchase those from companies who pay the developers.

Yeah, this is the way. A big chunk of production setups will *always* want to have enterprise support ready for a central piece of their infrastructure, those who don't will soon learn that they then either need to spent more from their own maintenance person/cost pool or fail on providing an adequate service. Will quite some people take the free ride? Sure, but a lot of them still will contribute to a healthy community, and can be leveraged for providing a better enterprise experience, iow., that's a feature, not a bug.

If just providing ready-to-use binary builds threatens to fail your business case, your business case isn't worth much and will fail anyway...