Not all of them are "open core" in the sense that they have a core product and proprietary extensions (some just opensource everything they make), but a number of relevant companies around FOSS products: Gitlab, MariaDB Corporation, Blindside Networks (Big Blue Button), Qt Company, Mattermost Inc.
Which is all to say, if you write that post, I for one will read it :)
When Six Apart made Movable Type's license more restrictive in 2004, a portion of the userbase jumped over to WordPress. Another thing in WP's favor was ease of hosting, due to being written in PHP, vs Movable Type's Perl. This all led to a lot of momentum for WP; Automattic was founded after that, in 2005.
Confluent (Kafka), Redis Labs, Eucalyptus Systems Inc. (AWS clone, acquired by HP), Instructure (Canvas)
In that regard, "open core" (or open source for that matter) was never a business model — the business model always was bait and switch. Open was the bait.
But likely I have always been a little suspicious of "open source" and likely I am now over-simplifying.
Databricks has shown that you don't need a crazy license to win. I disagree with this article from my personal experiences and my industry experience but I respect you writing it. The business model is clearly alive though. Those companies that I listed have raised 100-200M in the past year at high velocities.
in terms of revenue justifying big valuations, how many healthy companies are there, really? ("spend $20M to make $3M..." = not healthy) What about ratio of OSS successes vs closed successes, esp w/ efficiency?
e.g., the biggest co there is databricks (and i continue to root for them!), and contrast w/ snowflake who started in a similar period, grew 10-20X bigger, and started more simply (get a clone of redshift without doing business w/ aws). worse, databricks took a lot of phd students many years with a lot of big corp funding before the vc's got involved: that's a high bar an oss co must hit vs not for adjacent high-growth spaces.
the good news for oss founders is VC's are warming to investing here, and sometimes, even before OSS traction. irrespective of profitability, the founders have a better chance of flipping it to be someone else's problem.
not necessarily as clear cut for community-minded co's though that want to be financially healthy for their community. it seems the bigger and more numerous successes are non-oss, and despite the many oss attempts, the big sustainable oss successes have to doubly succeed at what is already hard. If going OSS increased chance of success -- and didn't actively challenge success -- I'd expect relatively more successes by now. I wish all this wasn't so but it's hard to unsee...