Exact same boat here. My motivation died around 30 (34 now) once I realized I wasn't going to make any kind of impact on humanity. So now it's harder and harder to answer the question of "what's the point?". Whereas, drinks with friends or walks by the sea never seem to give rise to that question in the first place.

So even though I still like to read about interesting things, once any initial curiosity has been satisfied, I'm out, there is no depth to the learning anymore, and soon enough you forget it all anyway.