Secondly, being released under a permissive open source license definitely helped with its adoption. I was working as a senior developer in a UK Government department in 2013 and we had need for a full-text search engine for a project - and even before v1, ES was a contender, and it was eventually selected once v1 was released. This was largely due to a) ease of set-up/use and b) it’s release under an open source license. If it had been under AGPL, would we have still used it? Yes, probably - our specific use case wouldn’t have been affected by such a license, and the dept. was relatively open to more complex OSS licenses - but I have worked for several other orgs. where even just the AGPL would have resulted in a hard “no”.
Thirdly, ES has had contributions from a wide range of people. I honestly don’t know how I’d even begin to evaluate how much value ES has got from community contributions, but I feel it’s likely to be greater than the costs of managing those contributions.
But of course eventually Elastic got funding and had shareholders to placate. I don’t really have much sympathy for them about this conflict - their early choices were in part clearly made to maximise their value, and they decided to cash in on that value at a later date - the fact that those decisions had implications for their value should have been somewhat obvious to any investor who did any due diligence. I’m still not entirely convinced that the open source model is antithetical to commercialisation, but I think it does highlight how early decisions around OSS licensing can affect such processes.