Wrong: "Weaning is the process of gradually introducing a mammal infant to what will be its adult diet and withdrawing the supply of its mother's milk."
Instant gratification becomes our adult diet.

You misused the word "weaned". Look it up. You also did not define "we." Were you speaking for yourself?

We were weaned on instant gratification, and glean no satisfaction from planning for the future.

We're not adapted for long-term thinking or thinking about things far from us.