You have to limit what are you going to learn, otherwise you will have no time to build anything. So you have to pick carefully. Generally, the open technologi

You have to limit what are you going to learn, otherwise you will have no time to build anything. So you have to pick carefully. Generally, the open technologies were proved to be useful in long-term, and even when they change, they change evolutionary. You don't have big bumps and complete u-turns in your progress. There is also no-one, who suddenly decides that the technology you were invested into is suddenly not profitable for them and ceases development. The open source technologies die only then, when they are not useful to anyone. So basically, strong preference for open technologies is a pragmatic risk mitigation and investment protection.