You can't buy time. And a demanding job that'll get you that 20k/month will start to degrade your health at some point, rather sooner than later. And in most of the world even 'only' 1/4 of that will make sure you're living a quality life, esp if you can earn it with part time work while spending extra free time exactly how you want to.

But hey, people finding happiness in owning more than they can spend or use are free to work as much as they possibly can.