So I have heard people sometimes say the reason for no aliens is that complex life requires so many coincidences it is just incredibly unlikely to indecently arise anywhere else in the universe. I think it is a bit arrogant to assume all life has to mimic life found here on Earth, so forgetting the goldilocks zone for a minute, you still need life to emerge from nothing over the course of billions of years. Then you need complex life to emerge from that, and eventually civilization. But you know what else you need?
Extinction.
No extinction means no fossil fuels means no industrial revolution means no spacefaring. If it wasn't for the dinosaurs, we would have nothing. Makes you wonder what we're here for.
I conclude that any advanced alien lifeform that gets to this stage will have to use a source of power not used so much on Earth. Hydro and Thermal seem unlikely, it's less portable and requires huge facilities, so it will probably have to something else. I imagine rivers of liquid gas, a space-faring civilization built upon lakes made up entirely of methane.
Edit:
It has been brought to my attention that fossil fuels are not in fact made up of ancient dead dinosaurs, and even if they were, we wouldn't need a meteor to make this happen. I just like Dinos 
The idea that fossil fuels are required for intelligent life to visit space is also human-centric, basically just looking at our own history of how we did it and saying, "that's the only way". But really it only requires industry to synthesize a propellant - or to use a different technological entirely.
When it comes to calculations trying to answer the question of why we haven't observed smart aliens, the most important fact is that all of the numbers are 100% fiction and if they're off by a few orders of magnitude each (which we should expect) then the "insights" disappear.