Just commenting on the aside, we should be careful about painting with an overly broad brush. Each of these companies and organizations is different, at least two you've mentioned are fully opensource afaik not open core (Redhat and Sentry). Redhat continues to do tons of opensource work across many ecosystems, kubernetes, linux kernel, gnome, etc. The Redhat sw model isn't open core, because what they sell isn't proprietary afaict its a support with updates model, that they also distribute under a different brand then the opensource (fedora/centos/openshift okd). Additionally we're talking about a multi-billion dollar company, seems like a success to me. For Sentry, their more focused on Saas platform, but afaics an on premise distribution model doesn't reference a commercial product thats differential to their opensource repos aka its not open core, afaics. [update] sentry on premise install docs https://docs.sentry.io/server/installation/
RHEL, as far as I know, is not available as a nice installable package without a subscription, at least to run in production. CENTOS was started as a separate entity to make bundling the RHEL source in to easily installable distributions more straightforward, as Red Hat made it difficult.
As far as Sentry, I'm referring to the fact that they have not cut a release of their on-premise in some time, and features have started to diverge, though they assert they will reach parity with on-prem "at some point"
https://forum.sentry.io/t/when-will-a-new-version-be-tagged-... (Though again, like RedHat, the source is technically available...)
My main point is that OSS is at odds with making money.
Easily installed isn't part of the opensource definition, any more than source available means opensource. Calling companies that are pure opensource, open-core is misleading and detracts from the conversation, imo. Centos was a binary distribution because Redhat made redistributions of binary RHEL harder to distribute(images/logos/binaries/names via copyright/trademark), but that was part of their business model. The source however was available under opensource licenses, and most of that was from separate upstream communities, aka its linux distro (though they have lots of other products). Re sentry, if I can pull the repo and get the same bits under OSI approved license, its opensource to me. Again opensource isn't about release management practices and nice installers (although for sentry its just a docker run/build away). They might be part of good community of practices for sure though.
I'd say opensource business models are different and potentially more difficult, but there are plenty of companies selling/supporting/building opensource. The delta seems to be most vc backed companies sponsoring opensource have different expectations on growth/value extraction from customers. aka open-core is not really about opensource, its about selling proprietary products, so I'd prefer not to mis-label those who aren't doing that.
We can argue all day about following the spirit of something vs the letter of the law, but all four of those companies have direct business incentives to make it difficult for those wanting to use their software for free to do so. No surprise then that all have taken steps to dissuade free users or make things more challenging. You're arguing about labels, which is beside the point.
