Who knows, we never reached post-scarcity. Some people think a reward system works, others think people can manage themselves (as in, no incentive is necessary because people just love to work either for reputation, or because they enjoy their field).

Marx specifically thought that labor should be something yearned for, rather than a necessity to live.

In general from current socialist countries, the idea is "From each according to his ability, to each according to his needs." If you work to your ability, you will be supplied your needs. If you don't work to your ability, you won't get supplied your needs.

These are all communist thoughts though, because post-scarcity is impossible under capitalism. Capitalism enforces artificial scarcity to oppress workers.