I don't think this is true... while conversations may refer to certain sections or summarize certain things, topics of great depth require a lot of time. There's no substitute for reading the original source.
> One issue for me is that books are a very big time investment.
This is one of those "is this a feature or a bug?" situations. Reading for a long time slow you down on purpose. It's meant to create moments of critical thinking and inspiration. It's meant for you to sit down and truly think.
I do agree that, still, reading takes way too much time. I don't read a lot. I usually read on vacation/airplanes, or if I can't sleep at night. Because they take a long time, I'm also very picky about the books I _do_ end up reading. For learning things, though, I usually listen to podcasts or watch videos at 2x the speed.
And lastly.... have you tried reading fiction?