Redis Modules are more and more becoming an important part of the Redis ecosystem. I would imagine many features are going to be added as modules rather than as new commands in core Redis.

Not being able to offer these while RedisLabs can is what I think they're going for here.

It looks like you could still develop and ship your own modules, even for profit, along with core redis.

This seems much like the "You have access to the source, so you can go fix any issues you find" answer to any complaints about OSS.

Developing modules for any third party software means not only do you have to have the skills and resources available to implement it, you then have to maintain it on an ongoing basis. That's potentially a huge task for small operations.

That's the thing--it's just a copyright headache. If Amazon wants, they'll use Redis anyway.