The premise of the relevant discussion is that the marginal value of additional work and wages beyond the basic requirements is largely nothing. You cannot accrue meaningful savings, but still probably have enough disposable income to live comfortably enough, so it’s just a bad deal to work more.
Very simply, the marginal utility of additional wages is much lower than the cost of working them at the rates being paid.
Marginal utility changed with each unit.
They don't want to work some last x% because they're happy with their current condition. The ants work the last x% so that when they retire they can continue to live in the style to which they've become accustomed.
The young folks are being offered money. They don't think it's meaningful because it doesn't enable them to afford some item now. So they can either decline the money or increase their estimate of its utility by taking their future into account.
They both freeze to death but at least the grasshopper had fun during the short summer first.
https://read.gov/aesop/052.html