The point of open source wasn't to enable viable business models for companies like Elastic. The ASL is commercial-friendly, but the design of the license wasn't to enable any specific business model. It was to ensure the widest range of freedoms.
A lot is made of the way Amazon is "taking advantage" of the license, but they aren't. They're doing exactly what is allowed, what anyone is allowed.
IMHO, if you're releasing your work under an ASL-like license, then you're making a specific promise to the community about the freedoms related to your code. You're making a promise to all the adopters and contributors. The license is a promise (literally a contract) about what to expect from each other so that we can all contribute on the project together.
When an actor unilaterally changes that agreement, it's understandable some may be upset.
And while I know it's trendy of HN to discount non-profits like Apache as out of touch or old-school, they serve an important function in the open source ecosystem. As a non-profit, Apache doesn't really care too much what Amazon or any big or small tech company does with the code, as long as the original code remains open source and there is a community that can continue to work on it. The continuation of the community is paramount, above and beyond any one company's business model. We want software, particularly internet middleware, to be stable and last for generations.
When we take a long term view for the health of the interview, Elastic's move is great for Elastic, but not for the internet as a whole. Consider where we'll be if/when Elastic collapses. Right now, Elastic has plenty of fans, but we have no guarantee that they will remain competent, competitive, and innovative over time. If their hosted service suffers, their new license ensures that no one else can compete.
The advantage of broadly supported open source projects is that they can out last any one company (e.g. Sun) or any one person, so that we can build a technical commons for the future.