It is already everywhere
Google, Netflix, LinkedIn, etc. all use it. It has staying power because its already everywhere and that won’t change overnight.
It is flexible
It can be used for frontend or backend while providing excellent performance. It isn’t bound to any browser or operating system either. The only tool you need is a text editor.
It is easy to learn
Anyone can learn it without any tools besides a text editor and a browser on any OS. Internet tutorials, videos and forums make this one of the simplest and most accessible languages to learn. Also, you will be forced to bump into HTML and CSS in the process. These 3 together are the foundational building blocks of websites everywhere.
It has a great community
As mentioned before there are lots of resources for the beginner. The community is full of experts and newbies alike. As new problems arise, new solutions arise. The community as a whole is always growing and changing.
It has relevancy