My theory doesn't suggest that all people are equivalent. As I stated pure intellect lies in metacognition.

I also think that learning or solving problems is not deterministic algorithm, it's a heuristic. If it's heuristic there are lots of random elements and tuning.

Obviously, everybody have their own "hardware" limit determined by genes but often people make big mistake thinking they already reached their limit by simply getting stuck in some topic without seriously and very fundamentally reconsider their whole approach to the problem or learning process itself.

I think often in these situations, possible limit is much, much, much higher than one might think.

I'm not OP, but I don't think that was an intended implication. It is my understanding that the genetic component of intelligence is widely acknowledged. I think the OP's model is still valid and useful, despite genetically-driven differences.

True. Gene matters. But that does not mean we should give up hope. This is not being stubborn. This is just logical. Its like running two operating systems on a same hardware. One of them must be really faster than the other just because it has the instructions in different order and that's meta cognition. Keep changing the order of instructions, because we don't have a proof for the limit on the hardware.