Earlier quoted context omitted.
Amazon / Google / Microsoft made a massive mistake by not hiring Antirez, it's chump change for them to throw him $1-2M a year at him so he can work on Redis for them full time.
I mean I love redis, but Amazon Google and Microsoft all probably have readily available in memory key/value stores at hand. Throw a little money and they can make it redis compatible, so we wouldn't have to re-write any code. Redis is great as an off-the shelf component, but it's not exactly rocket science to re-implement for a big corporation. So redis doesn't really have any leverage in my opinion.
I suspect in the long run, Amazon will eventually "pay" the licensing fee for customers that demand "Redis". But they will push everyone else towards their in-house fork of Redis that they brand MemoryDB or whatever. You will pay more for the Redis licensed version and AWS will steer you away from it, but it will be there if you are adamant.
This is already happening with Aurora, which has Postgres and Mysql compatible versions. If your company is big enough for special pricing, then you know they want you on Aurora. The pricing discounts for Aurora are insane (50%+) compared to what you might get on a traditional Postgres of equivalent size (20%). They will probably do this with MemoryDB and Redis eventually. Redis is available if you really need it. But this other thing that they maintain is discountable to half the cost of the other one and it becomes a pretty obvious choice.