There's this strange myth that white collar workers try and find meaning or reward in their work. If the stars align so that the unquenchable thirst from your brain can be satiated with white collar work then great, keep going. But I suspect that work is just that, selling your time for survival and comfort in other parts of your life. It's even weirder that we place the onus of finding such meaning on the worker when we've built an economic system that expects them to behave like Homo Economicus; getting the best possible economic reward for the smallest possible input. Most of us don't have the luxury of pursuing challenge, putting food on the table is hard enough as it is.
There's plenty of meaning up for grabs in parts of life that don't have anything to do with money. I think as a species we've optimized for the wrong thing; there's a better life to be had with quality leisure time than the convenience lifestyle our current economy seems aimed at. Sell as little of your time for as much as you can get for it and invest that time where you're sure to derive meaning from it.