I'm sometimes very curious; however, I think the primary reason I'm not learning more is that I forget things very easily. This might just be me, or it might be fairly common.
Anyway, if you periodically blow away (lose track of, stop using) the external-memory tools that cue and reinforce your good habits, then there is a ceiling to your tools' sophistication, and your average set of tools will be significantly less powerful than the ceiling.
For example, I rewrote a programming-process helper recently and it's not that much different from the previous version, that I might have written two years ago.
Mostly, my tools are for programming, but I've had procedures and tools for systematic reading and retaining knowledge, procedures for evaluating arguments critically, procedures and tools for developing mathematical theories including proofs, conjectures, and examples.
To become stronger, you might have to plan for forgetting your current passions, and throw your memes/tools outwards like dandelion seeds or boomerangs, hoping that even after forgetting, you will re-encounter them. This suggests that even very personal tools need a certain sort of polish, in order to be taken up and re-adopted by your future self - small size, readmes, source distribution, good comments, extremely portable implementation, and so on, all help with reuptake.
(This also connects to my belief that you should not identify with your genes alone, but also your memes.)
Related to: Rationalization, Meditation on curiosity, Original Seeing.
Why aren’t you learning faster?
For me, one answer is: because I’m not asking questions. I blunder through conversations trying to “do my job”, or to look good, or elaborating my own theories, or allowing cached replies to come out of my mouth on autopilot. I blunder through readings, scanning my eyes over the words and letting thoughts strike me as they may. Rarely am I pulled by a specific desire to know.
And most of my learning happens at those rare times.
How about you? When you read, how often do you chase something? When you chat with your friends -- are you curious about how they’re doing, why their mouth twitched as they said that, or why exactly they disagree with you about X? When you sit down to write, or to do research -- are you asking yourself specific questions, and then answering them?
Are there certain situations in which you get most of your useful ideas -- situations you could put yourself in more often?
Lately, when I notice that I’m not curious about anything, I’ve been trying to interrupt whatever I’m doing. If I’m in a conversation, and neither I nor my interlocutor is trying to figure something out, I call a mini “halt, melt, and catch fire” (inside my head, at least), and ask myself what I want. Surely not stale conversations. If I’m writing, and I don’t like the sentence I just wrote -- instead of reshuffling the words in the hopes that the new version will just happen to be better, I ask myself what I don’t like about it.
Thus, for the past six months, several times a day, I've interrupted my thoughts and put them back on an “ask questions” track. (“Grrr, he said my argument was dishonest... Wait, is he right? What should it look like if he is?”; “I notice I feel hopeless about this paper writing. Maybe there’s something I should do differently?”) It's helping. I'm building the habit of interrupting myself when I'm "thinking" without trying to find something out, or taking actions that I expect won't accomplish anything. As a human, I’m probably stuck running on habits -- but I can at least change *which* habits I run on.