Silver Rank always increases and decreases.

Games Halo 5: Guardians
1

I have always have been the max Competitive Skill of Silver in any playlist for Arena. It always increases and decreases. I know I will never ever get Diamond, Gold, Platinum or Onyx because I am too stupid to do so. Does my profile disallows me to get any playlist rank better than Silver?

2

No. It just means that you lacked the wins needed to place gold / promote from silver

3

Silver 6 is the highest for silver btw in case u didint know