Unless we just happen to have evolved very early on compared to what's normal, we should expect a lot of intelligent life with just a little bit of variance on these numbers. And some of that could easily be millions of years old. Interestingly, even if a life form populated new solar systems at a rate of a thousand years per system (where each populated solar system in turn populates more of them), they'd still fill up the Galaxy in only a couple million years.
Unless "intelligent" life inevitably renders its local environment uninhabitable and collapses in short order - a proposition looking more likely by the day. It may be that the intelligence required to maximally exploit the local negentropy is strictly less than the intelligence required to not do that, despite being able to. Indeed it's difficult to see how the trait of "behaving responsibly with an entire planet" could evolve - the selection pressure is rather all-or-nothing.
This is my belief as well, although slightly different in how I phrase it: humans are incapable of seeing much beyond their own selfish desires, and as a result will wind up causing their own extermination. The denial of death is widespread and understandable: to truly consider existential demise is exhausting, and I suspect has been backgrounded for simple evolutionary reasons.
Regardless, the species is naturally incapable of averting averting crises that are foreseeable but distant.
Why is intelligence seen as some inescapable playbook of evolution?
Evolution has no agenda or goals, other than to select for survival. Most species on this planet have a low intelligence yet are successful, and don't seem to evolve into the direction of intelligence.
For every planet with intelligent life, there could be many more without it, no idea what that relationship might look like. I'm not suggesting it's the norm.
