We've also updated all our tender documents for future projects to include a requirement that we can query metrics and logs through an API or direct DB access.
A recent project I worked on identified over 500 applications whose only use is to provide monitoring to a bespoke system or tool. This isn't uncommon at a university as different faculties and departments will buy "the best tool for XYZ" without ever asking IT if perhaps there is a tool that is almost as good that we already have.
As well as the things you identified, I suspect that there's just a lot of mistrust of open source in the industrial world - there's that whole thing of perceived value being directly proportional to product cost, plus commercial vendors also tend to at least offer training and tech support, even if they're not always the most helpful.
I am curious in what regard nothing comes close to grafana? I am Currently paying a lot for citect and wonderware support across a couple dozen facilities.
The industrial historians solve the same problems - collect data at nodes that might have intermittent connectivity, send to a centralized server/service that can handle lots of data, and allow users to plot it.
I wonder if we’ll start to see more open source monitoring on the factory floor. While it will be easy for a product to work as well as industrial offerings, maybe their value is in the long term support (usually close to a decade) and supporter upgrade paths.