On the contrary, i see my fps all the time if i want, with fraps and other like software.
I also play with settings in games that i play a lot of, so i know exactly what features to disable to gain the maximum performance and at the minimum loss of IQ. Features such as setting shadow from HBAO/HDAO to SSAO etc, you can hardly notice the difference in the scene but the perf gains are big. Or particles from max to high etc etc. I have a fine control of what features to lower while maintaining high fps in games i frequent play.
As for adaptive sync lowering IQ in scenes that stress the GPU... what is it doing? Is it lowering FoV, draw distance, LoD, lighting, shadows etc? I rather be in control of my GPU to render a scene how I want, and not not let the GPU automatically adjust rendering quality.