Advanced species and civilisations are improbable but to rule out the existence of life of any kind (even bacteria) is unwise IMO. It should be left as an unknown.
On what basis are advanced species and civilisations improbable MT? The number of stars and planets in our known universe is practically infinite. Just because other civilisations haven't turned up and declared themselves (and there is good evidence that they have, but I'll put that to one side for a moment) doesn't mean other species don't exist.
I reckon given the right conditions life thrives, and evolves. Even if it's a one in a million where the right conditions occur, the sheer mind blowing number of stars and planets out there means there would be a massive number of advanced species. We know that there are a number of planets sit in the Goldilocks zone and we have scratched the smallest slither on the surface.
Firstly, the further away you look from the Earth, the further you are looking into the past. We're not looking at the current state.
Secondly, the Goldilocks zone is fairly broad. Essentially, a planet that exists from a Sun-like star a distance equivalent from Venus' orbit to just beyond Mars' orbit.
Add to that the composition and habitability of these exo-planets is uncertain. Some of these exo-planets have later turned out to be unhabitable after further investigation with improved modelling.
Then add such things as orbital effects which play a significant part in a planet's climate. The planet's tilt, the precession of the tilt, the variation in eccentricity of the orbit, etc ... all play a major role in such things as the rate and frequency of ice ages.
Changes in composition over time can have a major effect on life. Atmospheric Oxygen levels on Earth changing from 1% to the current ~21% a million years ago (off the top of my head) had a significant effect in allowing the evolution of megafauna.
The other planets in a solar system can also play a roll. Jupiter's gravity for instance 'protects' the Earth from long-period comets and such reduces the frequency of these comets colliding with the Earth. A major collision would be obviously devastating to life on Earth.
Essentially, I would argue the variabilities needed for the existence of advanced species on another world are just as great as the possible number of habitable planets in the universe. I'm not saying it's impossible but it's certainly improbable that advanced species and civilisations exist.