One result of the winner-takes-all system is that an elective majority is different from a governing majority. Even if theoretically elected to unfettered power, the majority must assuage the minority, or risk getting nothing done. FDR understood this well; not every President has. Some political entities in the U.S. have played with representational apportionment, but this risks weak governments which are able to act only when a consensus exists. Actually, not so different from the present. In the end, no system guarantees a "good" outcome. It always depends on the people elected to make it work. The current weakness of the US government is simply a reflection of deeply-felt values that differ widely. Expect nothing to change until a national consensus arises.
The flux you are seeing now has existed in varying degrees since the old consensus was shattered by the Viet Nam War. The lasting legacy of that war is the deepened distrust of the national government. In fact, to a lot of people, a government that cannot govern is a desirable outcome.
This should be taken with salt,