> The most dangerous thing that any developer can do is choose to work with only one framework or library

100% agree, still I found better results choosing a "main" framework/library to learn and then having a set of alternatives.

https://stateofjs.com/2017/front-end/results will give you an idea of where things are by December 2017. React is taking the lead, but Vue has great potential.

I personally worked with both and have VueDevTools and ReactDevTools extensions installed, and I am impressed by the number of websites React icon turns on compared to Vue. Which would mean is has a huge chance of becoming a standard for the next few years.