Ask HN: Sidebar sliders are too invisible?

The disappearing, low-contrast, narrow sidebar sliders are so invisible that they are way beyond the esthetic and design point and they already affects usability or even work effectiveness? I was wondering if it is something wrong with my eyes, my displays, my way of working with computers or rather the world has shifted to touch screens so much that sidebar sliders makes no more sense as now the proper way is to "touch everything with your finger". My overall feeling is that looking for a slider's position takes now much more time than before.