The average human may be plain unable to meaningfully stick with a problem for ten years. (That is, to actually productively work on the problem daily, not just have it on the to-do list and load up the data or whatever every so often.)

I don't think working every day on the problem is necessary. For a lot of problems visiting them monthly does a lot.

If you want to formalize the approach it's something like: I have learned something new X, how does X related to problem Y1 to Yn?

If you inform yourself widely, I think you have the potential to contribute. Most people aren't intellectual because they don't invest any effort in being intellectual.

Since IQ correlates with practically everything, including conscientousness

Given that papers get published with titles like Why is Conscientiousness negatively correlated with intelligence? I don't think that's the case.