> only a few billion planets with complex life?

Or trillions or tens or ones. Depends on what number you put in the exponent. Currently, we don't have useful constraints on that figure.

(A lot of popular astrobiology pulls the "if we could only get 1% of the market we'd be billionaires" schtick.)

The astrobiology schtick is just a what if thought experiment though, and nothing proven nor claimed to be fact. It's just a way to show that the scale of the universe is "hugely, mind-bogglingly big" while trying to pull a number that our squishy lobes could comprehend. If 1% of mind-bogglingly huge number, then 1% of that, then 1% of that yields a still mind-bogglingly big number. The laws of large numbers would suggest something as well. Otherwise, "its an awful waste of space"

Sure. The point is 1% is a huge fraction for a lot of things. Market share. And many reaction cross sections.