$4,752 of extra savings a year is an absolutely MASSIVE amount for a middle class person. For example, if you're already saving $20k a year, that will bump up savings to almost $25k.
Then, this is just one source of additional savings. Cut further on services you don't really need (coffee at $4 a pop, $150/mo cable TV bill, etc.) and now we're talking some serious money.
If people stop buying things, they won't get the 33%-off savings. Don't double-count.
Middle class people don't spend enough in a year ($40k per person, tops?) to be rich even if they spent NONE of it.
And if they "got rich" saving money, what is that money for? To be spent on desirables.
Then, this is just one source of additional savings. Cut further on services you don't really need (coffee at $4 a pop, $150/mo cable TV bill, etc.) and now we're talking some serious money.