Right. Elastic didn't do it for generosity, either. But your point that ES got benefited from the business friendly license and then made it closed source just supports my point that businesses will just maintain their forked-version rather than putting it out there in the open. I'm all in for open-source software, but I'm just making a point that business-friendly open source licenses don't necessarily beget more open source code. Sometimes a restrictive open source license like (GPL) is far better than a business-friendly license for open source community.
GPL would not have had any effect in Elastics case, private forks are legal under the GPL. AGPL might have. But then again, AGPL would have been a major hindrance for corporate adoption since no one wants to open source their whole tech stack just to add search.
The interesting thing is that Elasticsearch has an open source competitor, Apache Solr. The community around Solr is organized more like the community around postgres - multiple actors that work on a shared project that not a single one controls. Anyone of them could make a proprietary fork, but the others could quickly band together and punish that.
So the lesson to draw here is maybe that the license itself matters less, but what matters is whether there's a single actor in control of the project. Because in the end, the reason why Elastic could pull this stunt is less about the license, but about the copyright ownership and control over the project. They owned the code, had a CLA in place for any contribution and thus could do whatever, license be damned.
AGPL or GPL doesn't matter here - AWS were fully compliant with the AGPL in their use of ElasticSearch (they were already releasing all the code, even though they were providing it as a managed service).
AGPL would probably matter here - it's viral and would potentially require open sourcing all software in the stack that interacts with it, for example the systems that AWS uses to manage the Elasticsearch instances. In any case, AGPL is on the "do not use" list for many enterprises, regardless whether it would have any effect or not in the specific case. Engineers that want to use AGPL software often would have to go through legal, so it does stifle corporate adoption.
The only difference between the AGPL and the GPL is whether offering access to the software over a network is considered distribution or not by the license itself (AGPL says yes, GPL says no). Otherwise, they are both exactly as viral.
You are quite right to some extent about corporate policy differences. I think the status quo might be trending away from this extreme caution, but it's still there in many corps.
Edit: grammar, spellings