This was so obvious when it suddenly dawned on me. The reason why I mostly end up with very few layers in my Photoshop editing is that I tend to try and make all the curve adjustment in one layer. One layer for dodging and burning, one layer for correcting colors and so on. So figuratively speaking, I wanted to paint the entire scene without lifting the brush from the canvas.
When I analyzed Diane Varners example a bit closer, I see her doing many small adjustments, and when I looked back at some of my more successful images, that is also what I have done. While doing this, you should pay attention to whether you start to create layers that reverse the effect of a previous layer instead of removing the previous. When I have done this, I have made my worst failures.
So, adding many small and subtle adjustments seems like an easier approach than doing it all in one stroke. And why not, this is what you do if you draw or paint.