As you wander through the big world that is Toril, you probably notic that your not in Kansas anymore. Dragons, trolls, spiders the size of really big rocks, elves etc. In essens this is not a very normal place. Weird things happen, such as: one discovers that ones father is the Lord of Murder, some dragons take the time to friendly banter even coax you to perform the odd quest, and the like.
Question: Why aren't there more opportunities to get more innate abilities? I mean with everything else going on, an adventurer should during his career somehow gain some small innate abilities through quests or gold.

I've heard that at one time, there were other innate abilities that could be gained once you defeated each of The Five. What you got depended on your alignment. For whatever reason, they canned the plans but left the abilities in the programming. I've also heard that if you have/use SK, you can incorporate those abilities into your character.

Again, just what I've heard. I've been too chicken to try them out to see what they can do.

welcome to sorcerer's place friend. I believe that you understand that the innate abilities are something you are born with not gain through quest or gold. Your character as well as mine gains these abilities in different levels because this represents the mastery you (he) have gained over the dark side of him. These abilities are not being bought or given as a prize. I think that if you had played BG I you would remember that your character gained these abilities after some dreams concerning Bhaal and the attempt to get hold of you,not after quests.

High level abilities.

There is a also a MOD that touches on what Spelladonna said - released so that each of the five tests gave you an innate ability - they are in the game whatever just not implemented - the MOD is dowloadable from (fanfare) Sorcerers Place.