It's generally a bad idea to have that kind of a disconnect. Ideally, you want a diamond distribution of assets. Tiny lower socioeconomic class, tiny high socioeconomic class, extremely large middle class. Tends to be a sign of a very healthy country. When you get a huge under class and a shrinking middle class, it means your economic system is screwed up.
Political issues tend to crop up shortly thereafter.
Last time this was a big political problem, we got FDR and a slew of socialist programs. Problem is, we already have some socialist programs, as well as a matching ballooning debt issue. Toss in inflation, wage stagnation, increased automation in manufacturing, etc. I suspect there will be political problems from this in the near term.