Actually, a good share of Americans think they are Middle Class, despite their rather straitened circumstances.
Commies (and sociologists) define "middle class" quite differently than you do here. You define it as being able to:
quote="schopenhauer1;d12437"]to live in a house, buy some entertainment goods, a car, have all their daily living met[/quote]
That just describes people who are making ends meet.
There are roughly 3 classes (in the real world, not in theory): The working class -- the people who provide the labor to drive the economy -- everybody from agricultural workers picking tomatoes to people charting sales of goods in a corporate office tower. Teachers, nurses, laboratory workers, plumbers, electricians, sales, accounting, car repair, toilet cleaners, etc. (Workers produce all wealth.). Workers have a small share of all the wealth.
The ruling class is the small group of people who actually own the machinery of the economy -- land, factories, mines, warehouses, railroads, stores, banks, etc. Some of their names are familiar: Rockefeller, Ford, Gates, Dupont, etc. Most of these people you have never heard of unless you specialize in tracking large wealth. This group calls the shots for their own benefit. They possess most of the wealth,
The middle class consists of a fairly small group of people who manage the economy at a fairly high level; they are also the professionals who provide special services -- lawyers, doctors, dentists, polling, planning, professors, high level engineers, and so forth. They quite often have independent practices (otherwise known as jobs). The members of the "middle class" tend to be quite financially comfortable.
So, what you are asking is unclear. What if everybody became middle class as it is officially defined? You'd have 130,000,000 doing what 20 million do now. Who, then, would do the basic work o society?
Are you asking what would happen if everybody in the working class (who call themselves middle class or jack shit) actually had more money? Well, they would experience less stress, that's for sure. They might be happier, but not a lot happier. You can buy only so much happiness with a 10% or 15% ncrease in income.You aren't proposing a revolution here, you are just rearranging the deck chairs.