But isn't that part of the point of open source? If you want people to have to pay for it in some way, it needs to be part of the license. The license is essentially free for all.
The licenses weren't conceived of with the thought of something like AWS. Now that we're in the midst of things that's changing but what is an officially supported open source license [0] is too slow so you can't use the OSS label if you've you're not using the approved licenses. Both Mongo and Elasticsearch have changed their licenses to prevent cloud players from taking advantage of their work and companies like Gitlab make a clear distinction between their FOSS parts and what they make money on by using two different licenses.
The issues are only a little over a half decade old now the OSS players are starting to figure it out.
Open source just doesn't mean anyone can use it, there's a definition to adhere to and and org managing that definition. [1]
Legality doesn't always cover everything because that would result in a lot of problems. People operate on the spirit of the law, not the actual words or at least they are supposed to.
* You have people that are ideologically driven (FSF)
* You have companies that Open Source as a weapon [0] (Chromium)
* You have projects that are very pragmatic. They believe it is the path to technical excellence.
* You have individuals do it for their resume
* You have individuals that do it just for fun :)
[0] https://www.gwern.net/Complement#open-source-as-a-strategic-...