I think repetitive development is boring but as you said, you build up classes, libraries to shorten the coding aspect, however, you will always find developers still re-writing the wheel for their specific app etc…(some just doing it for the sake of it too ) Kind of funny in a way that this still goes on.
We are still nowhere near getting combined programming languages so a common language can replace the menagerie of languages, learning curves, quirks etc..

What we should be working to is something of that ilk so the boredom or repetitiveness can be lessened, we can all work from the same page and then focus on the journey of creating uniqueness of the quest

But I think web development is very boring. Part of that is because for me the coding is the best part. I love to build and refine code! The idea, the application, even the graphics do nothing for me. Don’t get me wrong, I’m not some curmudgeon luddite railing on the modern world. I’ve embraced the graphical world wholeheartedly. But nothing brings the excitement as much as those abstract things that touch on the real science: thread management, device drivers, algorithms, et cetera, are the things I find the most interesting. But those skills are not widely sought and are really a niche anymore.

The problem with web development is it lends itself more to those with artistic flairs and less for those entrenched in computer science. But that’s just my perspective.