I really don't know how this hasn't been answered. How do I extract drums from a track?

Take a look at the Music Rebalance feature in iZotope RX. There are volume controls for both Bass and Percussion. These may get you some of the way there.

Yes - what there is out there really doesn't work too well, whatever the claims for it. You might like to read this thread (if you haven't already): Recent thread about removing drum tracks 

"Just found out it's actually pretty much impossible???"

You've just answered your own question!  The usual analogy for doing what you ask is that it's impossible to "unbake" a cake and restore all its ingredients to their primary state.