In terms of component complexity, i.e. how many components are used in a project and how they interact, I think that if anything, hardware is less complicated than software (comparing, maybe unfairly, a PCB for a consumer product, and a webshop). It's just that a fairly detailed understanding of each individual component on a PCB is needed to create something which works. On the other hand, the trend (for better or for worse) in software is to just use more and more libraries and abstractions with little thought on how they might interfere with each other. And it usually works, making the barrier to entry ever lower.