Dependancies introduce unnecessary LOC and features which are, more and more, just written by LLMs themselves. It is easier to just write the necessary functionality directly. Whether that is more maintainable or not is a bit YMMV at this stage, but I would wager it is improving.
Don't get me wrong, I'm not a luddite, I use claude code and cursor but the code generated by either of those is nowhere near what I'd call good maintainable code and I end up having to rewrite/refactor a big portion before it's in any halfway decent state.
That said with the most egregious packages like left-pad etc in nodejs world it was always a better idea to build your own instead of depending on that.