Combination of both. You can't realistically be the best at something if you dont have a natural affinity for it. You can throw footballs 24 hrs a day and never be as good as Tom Brady; hell maybe never as good as a college level player. Sometimes, it just isn't in the cards. I hate to be the bearer of bad news, but if you played for 6 months and aren't already plat or higher, then you probably wont ever be challenger. Most good players mention reaching plat in their first season of ranked, etc.
That doesnt mean you cant get better. You could probably eventually at least get plat or diamond if you spammed games, mained a champ, and focused on getting better. Ranked is a time investment. Just your curve is going to be slow and not peak as high as talented players. Some people are just going to be better than you in a shorter amount of time, or always better. It didnt matter how much I practiced shooting ppl back when I played FPS games; I had a RL friend who was always simply better. I practiced all day, every day, just spamming games. He log on just wreck games, me, people, tournaments, get called a cheater, etc. As another poster said, at some point hard work won't take you any farther. I doubt you are anywhere close to that point. Especially since league doesnt really require that amazing of eye-hand coordination or reflexes. There are high rated Garen/Annie/Warwick mains for god's sake. It doesnt take much eye-hand coordination to click R on people with Warwick, so if people can ride him to diamond, you probably can too when you gain enough game knowledge.
I know its nice dreaming. I dreamed about being a god Quake/Unreal player. I dreamed about being an amazing pool player. And I kept plugging at it. I never became godlike, but I did get a hell of a lot better. Just keep plugging away, and focus on getting better and not just on winning. I think just about anyone can hit plat or diamond with the right champs and enough time. Also, if you REALLY care about getting better, you have to start using your time wisely. Just spamming endless games without any direction is going to take you far longer to get better than spamming them with a purpose. Its like any practice regimen. Hell, its like studying. I was always a cram study person. Sometimes I would try the 2-3 week long 1-2 hour a day study sessions, but I always did WORSE on tests. Because large portions of that time was wasted. Not paying attention, not studying hard, piddling, not even really trying to learn, just putting the time in. But when I last minute crammed, I was focused as hell becuase its now or never. I would always make A's. I remembered far more shit, because I used my 4-5 hour cram session FAR more efficiently and better than my 2-3 week study session. I crammed my way all the way through college.
Anyways, dont let not being a pro discourage you. You may not have the talent to be a pro player, but you can always be a streamer, or probably a high elo playe with enough practice, mainly because league has ways to circumvent "talent." Namely, incredibly easy to play champs that don't require you to have the reflexes or precision of a Quake/CS:Go player to succeed. Like I said, if people can main crap like Warwick and Garen to diamond, anyone can with enough practice.