From a financial standpoint, it depends. The range that is front-end covers a vast range of talent. A person could be labeled front-end while theming WordPress websites, while another person is also front-end working on a large product where engineering practices are important. In that range, the pay is going to greatly vary: $30k - $250k.
From an enjoyment standpoint, it too depends. If you enjoy solving user facing problems, then front-end is your thing. It isn't just about how to you retrieve the data, but how does the user interact with querying and then reading the results.
The front-end landscape does appear scary, but you need to realize that you are seeing a much wider landscape than you are with Scala and Ruby. Compare the front-end landscape to the data storage landscape. You got MySQL, MS SQL, Oracle, Redis, Mongo, Solr, Active Record, Datamapper, Hadoop, etc. If you tried to master all of it and follow every new library that came out, you would go mad. So you focus on a certain area while occasionally looking around. Do the same thing for front-end. Do you want to be working on large-scale applications, then focus on things like React and TypeScript - things meant to solve large-scale issues. If you want to make brochure websites, then focus on jQuery and CSS.