The fact that Aliens aren't here and Drakes Equation indicates they should...
That is flat out wrong.
The Drake Equation merely identifies some of the variables we need to figure out so that one day we may calculate the odds of intelligent life out there, and how many species there may be.
Of the seven variables in the equation we have only a little information about two of them:
1.) The average rate of star formation in our galaxy per year
2.) The fraction of stars the have planets around them
Any even then, the information we have about those two variables is far from complete. Without more data, any calculation from the formula is simply a guess.