See Don Norman's Design of Everyday things.
https://www.nngroup.com/articles/progressive-disclosure/
https://www.nngroup.com/videos/positive-constraints-in-ux-wo...
It's a little harder to make an easy version
Making the progressive version is very difficult. Where you can please one audience with the powerful and easy versions, you can often disappoint both with the progressive version despite it taking much more effort.
In my personal experience, you're lucky if free software has the budget (time or money) to get to easy. There's very little free software that makes it to progressive.
So yes, it is hard to make the simple version. You have to have a very good understanding of what the user wants out of your product. Until you have this clarity, every feature seems important. Once you have this clarity you understand what the important features are. You make those features more prominent by giving them prime real estate, then tuck away the less important features in a less visible place. Simple things should be simple. Complex things only need to be possible.