Or when Facebook Messenger supports XMPP up until the point where their user base is big enough and they don't have to care about interop anymore?
Welcome to Software Business 101, everyone plays nice with the standards/alternatives/competition until they don't have to anymore. I never understood why Microsoft gets extra flak for this in 2016 - maybe they were particularly good at it 20 years ago, but every big player will play hardball if they get a chance.
The answer is to avoid single vendor lock-in under all circumstances, but Microsoft is hardly on a trajectory to become the single vendor for Ruby or any other Linux-first tech at the moment (ha!).