You're saying the same thing but with two different outcomes, as if by virtue of using open source tools you're not going to get stuck working at companies that

You're saying the same thing but with two different outcomes, as if by virtue of using open source tools you're not going to get stuck working at companies that also only use open source tools. Become experienced in open source tools so that you can work in companies that use open source tools. Become experienced in closed source tools so that you can work in companies that use closed source tools. It's the same thing so really it comes down to a matter of preference and experience. I am pretty much a Windows developer as that's generally been what I've done, and have very little experience writing code for Linux and other operating systems. I could do it in a pinch, and with some time I could adapt and become a more open source based developer, but that is not the environment where I am most productive.