The terms used here (SaaS and Open Core) are orthogonal. SaaS is a way to charge for software, Open Core is a way to license one. The comparison between them is

The terms used here (SaaS and Open Core) are orthogonal. SaaS is a way to charge for software, Open Core is a way to license one. The comparison between them is of the apples to oranges kind — not very meaningful. Instead, what it is alluded here seems to be a comparison of hosted-only SaaS versus hosted and on-premises SaaS (SaaS v2?) on the businesses' infrastructure. The fact that the latter appears more often in companies that open source some parts of their stack is probably coincidental. If anything, this is what my startup is doing, as well, so I'm speaking from personal experience. As a live example, we open source product for public mass communication (Aether, https://getaether.net https://getaether.net), and a hosted or on-prem SaaS for professional, private use cases like within-company comms (Aether Pro - still in development). This is useful, because not only it provides value for the public (open source part), it also is useful for businesses, in that it removes the burden of implementation, while allowing the companies to still retain their own data by hosting it on premises or on their own clouds in an airgapped manner. Had it been a regular SaaS, this would have been impossible.