Which OS is the future? I think it will be a Linux Disto, probably Ubuntu...
It's a great question! I work a lot with Azure, and we're increasingly seeing Linux. Microsoft themselves use Linux to run some of the Azure systems/services. Around 50% of workloads on Azure are now Linux as well - it continues to increase!
There are lots of Linux distributions in use. Though yes, Ubuntu, Redhat, CentOS are some of the more popular ones. Well, what matters is that Linux is overall the best OS to run for businesses. Hence, it probably won't be out-competed anytime in the near future.