The Clone Stamp tool has a button in its options that says "Turn on to ignore adjustment layers when cloning". It is hard to imagine as to why Adobe didn't do the same with the Eyedropper, it is equally important not only for creating artworks from scratch but photo retouching too.
When the Eyedropper is set to sample from All Layers, there should be also an option to ignore adjustment layers above the currently selected layer.
The lack of this feature in Photoshop makes art creation and photo retouching extremely difficult when adjustment layers are used.
To reproduce the problem:
Create several layers with some colors or images in them.
Add one or more adjustment layers on top that change the colors of all layers.
Select a layer to paint on.
Set the Eyedropper tool to sample from All Layers.
Pick the Brush tool, hold Alt to get to the Eyedropper and pick a color from any of the layers and paint.
The result is a different color because the Eyedropper picked the adjusted color and this makes painting and retouching in this natural way impossible.
The above steps is basically the most common workflow when a user paints or retouches a certain layer using the Brush tool while constantly picking colors form other areas of the image by holding Alt to get to the Eyedropper tool, similar to using the Clone Stamp Tool,
Even a »Current and Below«-setting for the Eyedropper Tool would be helpful, I guess.