I thought about this recently. It does not matter whether you are smart or not. Indeed it helps, but the actual success does not require you to be smart.
1) Showing up every day is worth more
Being consistent and accumulating work will bear fruit - guaranteed.
2) Work builds success, not your IQ
Instead of thinking, that you're very smart, you might even think you're dumber than the average and compensate for that with more work.
With that approach, you're not resting on your high intelligence and don't waste any precious potential.
Real-life anecdote
I found, that the perfect example is from my school time. Back then, colleagues compared themselves by (not their grades in this case) but their IQ points.
There were persons, that took such tests when they were 6+ years old and this made them rest on their high IQ. Like the score would fix anything in their lives somehow.
3) Working a lot teaches you a lot
If, for example, you are like me, a software developer and you're working more than just your daily work, by doing side projects here and there.
You will soon see that there is more. You will soon get a deeper understanding of what you do daily and maybe combine the learned from both worlds.
4) But "I need motivation"
Another quote, from one of my closest friends. "I need motiviation". In my opinion, this is just another excuse to do something, that you have to do to achieve your goals.
Let's say I want to graduate in a specific subject and I have to take a test for it. I want it and taking the test is the only way to achieve this. For the test, I need to learn a lot. I can't just say "Yes I will do it when I have the motivation". In such cases, I am the only person who is responsible for achieving my goal and I will be able to blame somebody else.
Waiting for the motivation to arise will make you waste a lot of precious time. There are days when I do not want to do something, but I still do it. Because that's the only way to achieve a specific goal.
Conclusion
You're not doing something because you're motivated. You do something because that's the only way to achieve a goal. What do you think? Share your thoughts in the comments!