Agreed. Many moving parts, and every vendor could (and did) add their own variant of the moving parts, to integrate with their hardware/software/... And of course they then try to sell that and not the "standard" implementations, so not enough engineering work goes into those and the core components. It's a "collaborative" project with stakeholders that try to compete where they can...

Visible also in things like the installation process (which for ages didn't have an "official" answer, so you had pay one of the big vendors to do it if you didn't want to try automate it yourself)