Because Big Brother is truly exceptional. Every one of his achievements is not something I can easily accomplish. Big Brother is a Grade Nine Alchemist, while I have no talent in Alchemy whatsoever. Even if I devoted ten years to studying Alchemy, my highest achievement would only be that of a low-level alchemist below the third grade.
The difference between Big Brother and me is like heaven and earth!
Moreover, Guo Linn knows that such an assumption is utterly impractical. He knows he indeed has no talent for Alchemy and couldn't possibly spend ten years focusing on it.
As for the formations set by Big Brother, I'm even more unable to reach that level. Becoming a Formation Master is said to be even harder than becoming an Alchemist, let alone one who can set formations like Big Brother; that's as difficult as ascending to the heavens.
