Are you sure the people you work with don't half ass everything because they lack skills and aren't getting proper training, or are trying to do too many tasks and fail at all of them as a result? I'm tempted to assume they bragged about it maybe, based on the rest of your comment, but it's easy to assume wrong.
Quiet quitting reminds me of "greve du zele" (zeal strike) where workers do exactly what their contract requires / work by the book. It is nothing new. Often to protest employers lack of flexibility, to show that the book is absurd or to highlight that all that extra work should be compensated appropriately. I guess the main difference is one is an organised protest while the other is individual decisions.
That said, everything I've read about quiet quitting sounds to me like a marketing ploy to give setting healthy boundaries a bad rep.
I'm sure there is a range from folks who simply stop being proactive to people who put more work into doing the least amount of work they can get away with than they would if they just worked. And sure, that may already mean others need to pick up the slack, but really it means there's probably a systemic issue with that employer.
If quiet quitting is a pain in the workplace, it probably means employers rely too much on employee zeal. Employers fully count on teams picking up each other's slack. Toyota (iirc) first figured out that bonding between team members improved productivity via slack pickupery and peer pressure. (Also that teams could find their own efficiencies and felt more motivated to work if they came up with or were involved in their own exploitation optimizations).
I'd love to see a proper study done to identify causes of quiet quitting, if it is linked to burnout, I wouldn't be surprised.
A simple solution to quiet quitting would be improving the workplace or giving out employment insurance when people quit, so they don't feel trapped in a bad situation. Not everyone can simply move to another job at will.