Here is my take on things. The best way to go from basic theory as described in the very first post, to a more accomplished stage is to learn folk songs, basic simple folk songs on your own. Thye will show you how to get your fingers going from different inversions. A piano player is a self made (wo) man. It's not in this book or that, its what the individual has mastered. No one can do this for you. Basic travelling across the keyboard in differnt methods is also important, for example, once you hacve mastered all your scales and chords in root position, try block chords in inversions gonig up asnd down the keyboard, once that is flowing freely, then try spearing out the chords fro their root position and adding 6th and ninths, then non chordal tones. This takes a LOT of practice but when this is done, then you get that flexibility that you need as a pop pianist.
Also work on repertiore, instead of learing from a book, take a song you want to learn, figure out yourself what the notes are. Even if you figure out only the first eight bars you will learn much more than if you learn the whole song from a book. Your ear wil improve and as with everything, if you persist, the process of learning a song without music notation will begin to9 get second nature and even instant. That's what a good pop pianist can do.
Caveat: Yes there are elements from certain styles - blues, stride, ballad etc that one needs some familiarity with, learning say a Jerry Lee Lewis song from a book will do wonders for your boogie. But, its got to be yours- you must own it