There are many good books and even videos of courses for those things you mention.
You can also join courses of interest if you've got a good university around you; as I haven't seen teachers objecting to outsiders participating in their course.
It is true that effort is required without immediate gratification (so it is hard to learn such subjects on your own), but it is feasible, because if the "hard CS" fields you mention don't peak your interest, I doubt they would've had an impact on you if you attended a CS college. Just go and learn, keeping in mind that it may take a while and you need to keep doing it.
There are indeed. However, without courses to direct you to them, many self-taught programmers don't realize that they should be reading them, or watching the lectures.
The problem isn't one of ability to learn. It's just that it's hard to figure out what you should be looking at.
I am a partially self taught programmer. I did take several courses in university to get a minor in computer science. These clued me in to the holes in my education. Otherwise, I might have figured it out eventually, but it would have been harder.
You can also join courses of interest if you've got a good university around you; as I haven't seen teachers objecting to outsiders participating in their course.
It is true that effort is required without immediate gratification (so it is hard to learn such subjects on your own), but it is feasible, because if the "hard CS" fields you mention don't peak your interest, I doubt they would've had an impact on you if you attended a CS college. Just go and learn, keeping in mind that it may take a while and you need to keep doing it.