Rank Limit

Do you believe anyone can reach any rank?

I have tried anything and everything. Watched 100s if not 1000s of hours of vods, game reviews, videos, guides, tips and tricks etc. Been playing the game for around 8+ years... Peaked D4 once (probably caused by sheer luck) and that was it, could never do it again. Been stuck platinum, now emerald, forever and no matter what I tried I feel I cannot improve anymore. Not implying I don't need improvement, I just feel like I can't do it, as if there is a limit to my abilities of processing and acting on the shit ton of information this game has.

Do you believe any rank is achievable by anyone or that each person has a set limit that cannot be surpassed no matter what?