I will work on easy stuff when it is necessary and stuff just needs to get done, and I recognise that a lot of work is about getting easy stuff done because value is often tied to tedium not to complexity, but to me the fun part is when value comes from making sense of the stuff that doesnt make sense currently.
At many workplaces, its awesome to be better, because -- while, yes, those kind of assignments come with it -- so does more advancement and security.
What sucks about being at the higher end of some teams is when other people come to you with trivial problems that they just can't be bothered to look into themselves. I'm happy to help people learn but I don't like being expected to do your job for you.
Joking aside, my idea is that a job isn't good for one as long as you feel you aren't learning anything but rather covering for other people. Monetary compensation is not enough for these kind of situations because the programmers I know generally are motivated not just by money but equally from the sense of accomplishment as well. It's not about "confirming that you are smarter and know more" as discussed in the article but rather the very basic feeling of getting things done.
The job should do something for you! You may be paid well, but you must feel like you're getting something out of it too; and if you have any sort of intrinsic motivation you can't expect to be satisfied with just money. It may be on you to find out what that is, there's no guarantee it will be technical in nature.
There are times when this won't be the case, though, and you'll need to grind.