Two words - stupidity and laziness.

Most people - an easy 60%, I'd say - are too stupid to figure things out and too lazy to bother.

Then there are the ones who are smart enough, but can't be arsed.

People like me, not very bright but trying their best to work things out.

Finally, the very few who have both the brains and energy to work it all out. Unfortunately at least half of those are completely selfish and act only for their own benefit. That includes sidelining or burying the other half!