You sound like a newbie with no real experience. Coming up with guitar parts in ten minutes is IMPROVISATION. Scales have little to do with it, if you come up with scales, you're going to get called for 1 session, and out. The purposes of practicing scales are many, not just one. I have made a living performing many many kinds of music, from classical and flamenco to folk, blues, rock, Brazilian and African, as well as quite a lot of jazz on the classical guitar as well as electric guitar, and I have played electric bass as well. I have done hundreds of recording sessions where I had to come up with parts, and I have accompanied dozens of singers who wanted me to improvise obbligato behind them. All of these took a knowledge of the fingerboard, harmony, and theory, which I gleaned from studying, as well as practicing scales, arpeggios, and chord voicing. I have done some 10,000 gigs, only 5-10% of them were classical solo recitals. I have also produced several recordings, coming up with parts for others to play as well. Your stubborn insistence that everyone should practice scales so that they can come up with parts is really rather silly, since most musicians practice scales for coordination, speed, endurance, tone production and a variety of technical reasons, most don't practice scales to be able to improvise. And most classical guitarists aren't pursuing studio work. Teaching at a college is hardly a horrible job, by the way, in fact, it is a great way to live at a comfortable level while pursuing a concert career. Oh, and there is enough work to go around, at the top levels. Perhaps you'll find that out, one day.
Lester Devoe Flamenco Negra
Lester Devoe Flamenco Blanca
Aparicio Flamenco Blanca with RMC pickup
Bartolex 7-string with RMC pickup
Giannini 7-string with Shadow pickup
Sal Pace 7-string archtop