Lecturing people will never get people to work harder.
Incentives are the best way to do that—and that is a management issue—identify the incentives that work best for individual employees.
For some employees it may be money, for others a hope for promotion, others want a fancy office, others a fancy title, others want social validation (awards), others want to be left alone and given a lot of “running room” etc. Everyone is different.
Good managers know how to handle the complexity—bad managers have no clue.
That may all be true, but I don’t know how it relates to “quiet quitting.” Bad managers aren’t a new thing. What IS a recent phenomenon is the collapse of trust and confidence among employees, business leaders and government officials in each other in this post-COVID world.