How is the expected career growth for Linux system Administrators ?
If you have good expertise on Linux OS, Networks, Administration and Troubleshooting, you would have superb growth as a Linux Administrator/Operations Engineer/Site Reliability Engineer/Devops Engineer.
Almost all top web companies in the world including Facebook, Twitter, Netflix, Amazon, and how could we forget Google, use linux based infrastructures on the server side. I dont have to tell you the size and scale at which they operate. To maintain this infrastructure, they obviously need linux geeks.
Almost everything we do today, we have an app for it. To order food, to call a plumber, to call a cab, to track health parameters, to read books, to connect with friends etc. Now have you ever thought about how many users does WhatsApp, or Uber, or in India Flipkart, Zomato, Ola supports? Where does the data for each of them get stored, retrieved, processed? You need huge backend infrastructure, most likely on cloud, which again uses linux servers.
A lot of devices including home routers, DTH, Smart TVs, Car Computers use embedded or a customized version of linux. Now who needs to created, manage those images? Ofcourse someone with expertise on linux.