Lord, that was well said! But I'm guilty as charged...I don't know any more than two scales.
I really do need to practice them more.
Right now I am working on the incredible Bach Fugue in A minor, transcription by Julio Prol, and it is a great challenge mostly because of its length. I can read very well but there are technical challenges. Scales would probably help.
I know that, being 54 yrs of age, I may never get this thing memorized...but I don't care...it just amazes me so much that even the first few measures can come out of me! I love that piece and it's one of my favorite Bach pieces that has been transcribed for the guitar.
I have the Segovia scales but only have two of them memorized. I think I will add another two per week, for now, and keep going.