I do think there is a place for royalty based software. Free for personal and development use. For production use, you pay a small royalty to have it on the cloud. It's a win win on both sides. User gets managed offering + support + ability to look at source code, db/service authors get sustainable revenue, cloud providers get their usual PaaS cut.
Here's what Salvatore has to say (from http://antirez.com/news/120):
"About myself, I’ll keep writing BSD code for Redis. For Redis modules I’ll develop, such as Disque, I’ll pick AGPL instead, for similar reasons: we live in a “Cloud-poly”, so it’s a good idea to go forward with licenses that will force other SaaS companies to redistribute back their improvements. However this does not apply to Redis itself. Redis at this point is a 10 years collective effort, the base for many other things that we can do together, and this base must be as available as possible, that is, BSD licensed."
Running a half-billion dollar company after raising $150M in funding is not nothing.