The disappearing Middle class Is more to do with the basic lack of need for middle management.
More and more businesses have got rid of a majority of supervisory positions as well as virtually all general management.
and unskilled work is now almost extinct.
Many companies now have a solid ground highly skilled workers who are largely self managing, and answering directly to senior managers at director level. Some of these skilled workers might be classed as "Team Leaders" but with very few management benefits. The management of such companies has become extremely flat. I noticed this trend in the early 80's in the UK.
The problem today is that a vast majority of the money and assets circulates at the top level. And Infrastructure, local government, health and social services No longer have a tax base to support them. As the top echelon have divorced them selves from supporting the majority, as was historically the case in the now not so recent past.
The result is a financial and tax system, that is not fit for purpose, with the majority missing out on any benefit from the explosion of "On line" and the digital world, which underlies much of today's business world, but which as a global entity, contributes very little to the tax and spend economy, either locally or nationally.
The poor are neither needed nor supported.