We evolved to spread our genes better, yes, but how does perceiving reality as best as we can follow from that? Both things are kinda orthogonal I'd say.
> Turning them off doesn't manifest joy but a genetic dead-end, in aggregate.
Everything ends, anyway. So at worst it'd be a dead end just like everything else :P And concepts like "chair" or "puredemo" or anything we talk or think about are really more concepts than tangible, discrete entities, you might also say they're made up. They can be useful shorthands, but when they take on a life of their own in our minds, when we think the symbol is the thing, that's where things get kinda pathetic, and not rarely it turns into a sort of pyramid scheme where we have to make up more shit to defend the delusions we already are invested in. Considering neuroscience, I'd even say we are willfully overriding what we discover because we like the delusion of ego better.
And considering what humanity "in aggregate" is up to, how we pollute and destroy, I would say the latest word in the effectiveness of ego to "survive" isn't spoken yet. It's not like there is this alternate Earth where people pay attention to people like Buddha or Erich Fromm we can compare ours to.
To me saying "we" have evolved to be this way for obvious reaons is like saying "this person is a heroin addict because that's obviously the best way get them going each day", without comparing them to a non-junkie in earnest. If you think not being possessed by ego means just meditating all day or doing nothing, you're wrong, from what I understand and experienced it just means doing and being without having a fake narrative in your head about it you consider to be real and super cereal. Being deeply content and at peace feels great, too, and compared to that short bursts of "ego-based" happiness seem very flimsy.