>>535261016
Because each stat has a threshold in which it stops giving combat power.
I'll list it down.
>Anything beyond 6k attack doesn't give significant anymore combat power
>Excess crit rate (Beyond 100%) wont give any combat power
>Anything beyond 50% Pen stops giving significant combat power
>Crit dmg beyond 350% stops giving significant combat power
>Speed beyond 300 stops giving significant combat power
Overflowing a single stat will not improve Combat power. It's a balance of high substats reaching the cap.