What is with this new generation of developers (I don't mean new as in young since I meet people in their 40s espousing these ideas), who make all these high-minded arguments about how evil it is to profit off of someone else's work, when literally that's what proprietary software is for. If you don't want someone to make money with your code, don't give it away freely, sell it.
Instead, what Elastic did was they made a beautiful piece of open source software, licensed under Apache 2.0. Because it was Apache 2.0, organizations were comfortable building Elasticsearch into their stacks because they knew that they couldn't get Microsofted. Additionally because it was Apache 2.0, hundreds of contributors who are not affiliated with Elastic submitted patches to their codebase.
Elastic used its position as an open source maintainer to grow Elasticsearch to be one of the most important pieces of software in the world (nowhere as important as linux or arguably lucene but still in the top echelon), and then once it did that it decided to lie to the community, pull the rug out from under them and switch to proprietary.
Now to be clear, I actually think this won't even make them more money, it will just hurt their brand image and incentivize high-quality Apache 2.0 feature-rich forks, so really it's just an absurd blunder. But I am so unbelievably frustrated that people keep espousing this reverse entitlement attitude that you espoused here: the idea that an open source vendor gives away their software for free, intentionally, so that they can benefit from the community and vice versa, and then suddenly now somehow I'm an asshole if I've been operating a service that uses Elasticsearch. It's completely backwards logic.
To put it another way, as an open source maintainer, you don't owe anybody your time. You are free to tell the people opening github issues and bug tracker tickets to go fuck themselves. But similar, nobody owes you anything, so if you yell at someone using your free software for commercial purposes, now you're being the entitled asshole. They don't owe you any money.
You people seem to think open source just means "source available". It's SO MUCH MORE than that.
[/unhinged rant]