We get too blinded by our own language and culture to actually see the probabilities for what they are.
Number of habitable planets we have visited: 1
Number of habitable planets to develop intelligent life: 1
Empirical probability that habitable planets develop intelligent life: 100%
Life finds a way. Electric charges find a way. Gravity finds a way.
The belief that life is some kind of 'miracle' that is improbable is our biggest blunder, and it's reinforced by authoritarian cultural iconography (iconology?).
Unless a planet has a particular long-term hazard that destroys life, it probably has life.
If that life has been around for any period of time within an order of magnitude of Earth's, then it probably has developed highly advanced functionality within its environment.
Anthropocentric egoism makes us want to feel 'special', but even within our own environment, our so-called 'intelligence' is a bug, not a feature.
Any sufficiently advanced intelligence that realizes how to get into space should be able to find ways to be useful to its own children's planetary resources.
Dumb animals and plants have been sustainable for billions of years, but we can't seem to stop killing each other, let alone our environment.
The probability that life on another planet developed radios (most of our inventiveness has been accelerated by our wars and rapacity) is a question of their aggressiveness, not their intelligence.
We take aggressive competition for granted because it's all we know, and we haven't been able to intentionally avoid it yet.
Our peace-based science budgets are insignificant compared to our destruction-based marketing and war budgets.