It depends if they run this break-even to support bulk APIs and improved workflows or to profit on the content. This content was donated to Wikimedia with the intent of being reused. This isn't AWS and Elasticsearch (though I also argue that you shouldn't open source something you don't want people using); Wikimedia is a middleman, not the author.
Is your implication that there is something wrong about AWS running OSI-licensed open source software as a service?
In general your comment doesn't make much sense to me. First of all it assumes a highly biased position in the AWS vs Elasticsearch war, but furthermore it's not even clear that the two situations aren't comparable. In both cases something that was free is having something built on top of it.
BTW the whole idea of Wikimedia Enterprise is providing higher levels of service availability. It's not really about the "content" itself. It's analogous to when you have a user of some service of yours that is flooding the service with requests and causing performance issues. A common pattern is to convert them into a paying customer and give them some guarantees about availability, while using that revenue to make sure there's enough hardware / engineering time to keep things running smoothly.
Finally, the "middleman vs author" distinction you introduce is entirely irrelevant. To use the Elastic example, it doesn't matter who wrote the software, what matters is it was written under a permissive license, and therefore the author of a given code doesn't have any "ownership". Similarly, someone who contributes to Wikipedia doesn't own that content either. In both cases the actor is contributing to the commons and has no expectation to put any restrictions on their contribution.
