Depends on what you're optimising your life for. Money is very easy to measure, work/life balance, family and other factors are all incredibly difficult to measure and are arguably more important. Plenty of relatively poor people have extremely happy lives.
Maybe that's what many smart people choose and why they are not rich.
While the working class always have to work to survive, it is also possible for someone in the middle class and even the upper class to also have to work to survive.
In both the middle and upper class cases, if the capital portion of one's position is insufficient to cover one's survival needs, then the labor component remains necessary to their survival. In other words, they have to work to survive even though they have capital to take them out of the working class.
It is not so simple at all.
[1] Some might call it upper-middle class instead, but the concepts remain the same.
Yes, there will be a level of income below which you will have to work.
Yes, there will also be a level of income above which you will certainly not have to work, given half-decent management of your wealth.
And yes, there will be an area in between where you may or may not need to work.
We noticed. Oh well. Can't understand everything, I suppose.