Hopefully, you're learning that new tool to achieve some worthwhile goal?

For example, I recently had to learn a desktop programming toolkit in Python, which I found very tedious and uninteresting. But knowing that I was doing it to help a team of engineers design a new kind of lightweight electric vehicle really drove me to put my heart in it.

Even when your project isn't aiming for such impacts, just putting (good) food on the table of your family can be a motivation I guess.

Surely, I do care about putting (good) food on the table and that seems the only motivation that keeps me doing this. But it used to be more manageable in the past and I certainly do miss those times when when you learned something new you felt empowered and almost giddy with joy. That happens less and less and I feel the dread coming down in advance when the new fad comes in and having to learn something new that isn't just better, in many cases something arguably worse and needlessly more complicated. Recently I had to develop an app in Microsoft Powerapps and while I admit to some good business uses the whole experience was an exercise in frustration. And it felt more like monkey around than programming if you know what I mean.

I know what you mean, and I feel for you.

That said, what forces you to follow fads? I've basically stopped doing it when I got started with Clojure about 6 years ago and it's been fine. It does take some convincing to use that for a project sometimes, but the feeling of empowerment has not faded, and compared to JavaScript churn the still waters of the Clojure ecosystem are quite enjoyable. My point being, fads are not necessarily a fatality.