Generally speaking, the winner of SGP2 is way behind a regular GP1 rider. After winning GP2 series and GP after GP getting beat by top riders could demoralise the young lad and set him back.
When Martin Vaculick came to GP1 he did well initially....but then didn't bother with GP1 fora few years to give himself time to mature as a rider. He came back into GP1, with more experience, came 2nd in GP1 just couple years ago. Sadly this year not performed too well, maybe he carrying an injury or something.
Just after Fricke winning SGP2 came Drabik and Smektala, between them they won 3 GP2 on the trot. Neither of them yet in the GP1 series full time, Jaimon Lidsey the same. I think Jan Kvech was 2nd in GP2 just 3 or 4 years ago, he will come back in 2 or 3 years better then he is now, hes picked up the experience.... it was just too soon for him.