IMHO "open core" is not a good idea in the first place.

Open source is about an open community, open contributions, the multiplier you get from contributions from multiple companies. That way open source is a win-win. Companies benefit from each other's contributions.

It's _not_ about just showing the code or a free-for-all.

Once you have free and non-free tiers it's already broken. The incentives no longer align.

I'm being paid in part to work on the open source projects that we utilize for our service(s). Some of those we started, some of those we're contributing to, but we _own_ none of them. We handed them off to external entities (Apache and others) for governance and we actively encourage others to participate.