The odds of you becoming a great or even the best player are determined by only yourself. If you put the time and effort in, you could make it happen.
On a side note, I really hope that NRS does something with their next MK game to keep a good amount of people playing it. It's kind of depressing that every time I log on I see maybe 100 people on average.
That first half of your post is super wise advice

.
Anytime you think you hit a wall or ceiling, many people myself included tend to think, "man this is too difficult I'll never get as good as Brady or reo." but truth is you can. If I compared the hours of my time in mk vs their times. I bet my time playing is a joke. For a long while I remember Tom saying he would play 6hours at the very least a day.
I barely do that much time in a week.
Another thing is practicing the right way. Just playing the game for experience isn't enough. You have to focus train Many aspects of your game.
For example,
Work on specifically only what your opponent is doing. And find patterns even if it makes you lose you are improving your ability to read your opponent. Then you can work on adapting to your reads. Aspects like these can some times be enhanced more productively if you spent time focusing on just that aspect. Playing online can also lead you to believe you're good enough, especially when you fight noobs or evenly matched players all day. Find that guy online that destroys you. And use him as a reminder you need to learn more.
There are many many many mental barriers a pro must overcome, I know a lot of them, and I can share how I overcame them. I'm no pro at MK9, but that's because of my lack of self discipline. But I played SSBM and SC2 competitively, so I know what needs to be done to get good. And it's all up to you.
Now...
Some peoples brains work different than others, perhaps you and a friend spend the exact same amount of time learning, and learning the same things. On may exceed the other in skill and this has only to do with previous life experiences. Perhaps solving math equations well or Logic puzzles as a kid helps give that edge? Who knows, but it just means that some people have to work harder than others. Fair? Up to you to decide if the time spent to get really good is worth it.