I'm struggling to form a definitive statement about my thoughts here, but I'll give it a try:

Every (useful) abstraction that aims to make an action easier will have to be more complex inside than doing the action itself.

Would love for someone to challenge this or find better words. But honestly, if that's not the case, you end up with something like leftPad. Libraries also almost always cover more than one use case, which also leads to them being more complex than a simple tailored solution.