That's a possibility or perhaps they will work less and enjoy their family, relationships, exercise, nature and art more. Maybe they'll decide to pay off their loans or save for retirement or their kids education or donate to a charity. Even if they end up buying something at least they stopped to think about it and committed to it knowing what it took to earn, rather than just hitting the checkout button with a reflex action. Maybe during that time they'll choose to look in to the company they're buying from and look for more sustainable alternatives.
Given that it's already declared to be "necessary" for people to have huge retirement saving to not live in penury .. yes? Also people could work less or retire earlier?
(Although more likely the economic contraction from wasting less stuff will cause incomes to go down!)