[kube-system]

You can do the same lock-in with most FOSS licenses. There’s no requirement to under any common license to document the code. And under the vast majority of them, you can deliver it as a service and be exempt from distributing your code too. Or, you can lock people in with complexity that, while anyone could legally expand on your code, they practically can not.

Data conversion may be a big cost factor in a small software deployment, but in a large deployment, it may only be a small portion of switching costs. There are a lot of switching costs that FOSS simply doesn’t address, particularly when labor, compliance, or legally related.