Pessimism, realism. Optimism, naïveté. Again, our intelligent species has been around for 200,000 years on a single planet. The universe has existed for 13.7 billion years. The average star is orbited by 10 planets, the average galaxy contains 100 billion stars, and there are an estimated 100 billion galaxies in the observable universe. And you are optimistically postulating that the only path for an intelligent species is inexorably forward to greater achievement, overcoming every existential obstacle encountered every time to the end of time, even as their problems become planetary in scope.
And yet, for all those places and for all that time for intelligent life to birth and grow and surpass our own limits and make itself known, none has. The only evidence we have of an intelligent life in the universe is our own. If what you are suggesting is accurate, the universe should be overflowing with intelligent life that we couldn't help but observe in some way. But we don't. We just observe a vast and empty void.
I'm all for the looking, and if we wind up with scientific observations that suggest a different conclusion is more likely, I'm happy to change my views. But what is most likely given what we know at this time is that simple life is likely out there, and fairly common. But intelligent life is rare and either hasn't developed or has hit some cap in its advancement before its disappearance from the universe.