A day full of intellectual stimulation and fun doesn't sound like a "waste" to me
Indeed, I already have a PhD (machine learning - 1992) and I worked in software development for 28 years, mostly doing what others told me to work on. I now get to do whatever I want.
I've always admired the way Knuth has spent his "retirement" and this little quote summarizes my goals too: "my role is to be on the bottom of things"
Sigh... I feel like, even five years ago you wouldn't have to explain this at HN, of all places. But now, it's partially HN, but also partially get-paid-lots-for-programming-news.
seems like a waste if youre not applying what you learn to anything practical.
Would you say the same to someone writing a novel, painting, or composing poetry?
if youre studying perspectives and color theory all day but never paint a picture then whats the point?
The poster's activities ("studying logic programming", "NLP experiments", "work on Haskell") are the equivalent of painting or composing poetry: a creative activity done for enjoyment. A better analogy for you (not that studying perspective and color theory couldn't be enjoyable in itself even if you don't paint... though of course it's a very different sort of activity from painting) may be "If you paint all day for your own pleasure but never exhibit or sell a picture then what's the point?" (not sure whether you would say that)