You don't have to have non-open-source components in order to make open source products attractive to consumers, enterprise, etc. "Open Core" is not the reason

You don't have to have non-open-source components in order to make open source products attractive to consumers, enterprise, etc. "Open Core" is not the reason why Ubuntu is "making headway in the UI department". It's the work of a large community of developers, many of whom do not work for Canonical, and indeed, work for competing companies. "Open Core" generally involves a single controlling stakeholder, which almost always means no properly enfranchised co-developers, no developer community, no collaborative innovation, etc.