I find writing front-end code, and process of learning new APIs, tools, and frameworks to do it in different ways, immensely interesting. I find I have the opposite of fatigue; building interesting browser-based software actually energizes me.

Ah, based on some other comments, I think I see what you mean with fatigue, because you have to use HTML/CSS/JS or something that compiles into this like Clojurescript and you still have to know what javascript is and how it works to get anything useful done on the front-end. I am praying for a really slick alternative to come soon, where we can capture clicks and events and still keep some sanity with regards to layout, structure, and tying things into the backend via message passing.

I think the tooling on front-end vs. backend has something to do with the end of the pipeline. Backend systems can be developed using multiple languages and frameworks that will ultimately run on only one platform. Front-end can be developed with multiple languages, but will ultimately be transpiled to JavaScript and rendered as HTML/CSS. Front-end has to accommodate multiple platforms and browsers.

To me it also feels like the "modern" tooling for front-end is created for front-end developers by backend-developers.

What do you mean, designing interfaces or getting code and components to play nicely together?