today's income inequality is because of technological improvements splitting out the middle because those types of jobs (highish cost, but repetitive and not highly skilled) are the ones ripe for automation. so you polarize and have fantastically paid people who automate (hey, how you doing plebs?), and then the lower tier people of people who it is just to expensive to automate their job at this juncture. but don't worry, such things are just a new frontier of things for us to do.
of course, there's a fallacy of the lump of labor here (the idea that there are only X amount of jobs in the world; this is a fallacy because as technology destroys some it enriches others. see any history book for examples). why is it that the middle jobs are dissapearring? they really aren't. something like a billion jobs have been created over the last decade but almost all of them were in developing countries. you see, labor is cheap there. since you can't move burger flippers over there, service jobs are the jobs that are left over here in the short term. in the long term, those middle people who were cut out by technological progress need to find something to do. or rather, their pay is too high for what they are doing; they need to compete with machines or change their jobs.
the future will only further this dynamic in terms of polarization. only those people who have a very specific set of traits and skills -- traits meaning they didn't really learn them from college or anything like that, but they are fantastically creative, for example -- will make it to the upper echelons.
to which i ask: why is this a bad thing? this is rewarding people based on merit. this doesn't mean that the lower end will be stuck in "poverty" or anything like it. comparative poverty, but i'm comparatively poor to many people today even though i make a lot of money. the income and wealth inequality today is nothing like what your precious marx was railing against. the people at the top are new wealth, people who have made names for themselves and made fortunes. and many of these people proceed to then give it away when they are done with it. they earned it, they made contributions to society far above what a taxi driver ever did. why shouldn't they be paid fantastically well? it is justice that these people are rich, same as it is justice that other people are poor