This is a question that has occupied my mind a lot
I think creativity is, to a great part, based on an individual's personality and abilities. There are often times where people tell you that they don't have much creativity and wouldn't have come up with xyz, even if it happens to be a run-of-the-mill idea you have everyday wherever you look.
Of course, that's because these people tend to do stuff different. How they approach situations and handle the results can differ vastly. Now, that doesn't mean they couldn't learn to be more creative about things - but I believe this would be the same thing as to ask a daydreamer to stop having his head in the clouds and look more realistic at his life and not overthinking it.
So, as there is a general difference, that difference also divides itself even more if you look at a creative person in more detail. There are people who have fantastic ideas for what they want to achieve, or they come up with stuff simply because they don't think too deeply about it. Then you have people like me who base all their ideas upon past experiences, their life and what they heard or saw maybe just yesterday. I think this group is actually the biggest one in regards of creative design, that's why it is quite difficult nowadays to come up with something completely new. People's minds stick to what worked and what they liked, and depending on how far they can spread their ideas around a topic determines how wide they can alternate from making a 1-on-1 copy design.
Finally, you have the rather small group of people, who despite our modern society, manage to create new things in small or even bigger scales. These are the people which work will be stuck in our minds the longest and shape the way results will be achieved and look like in the future.
So yes, at the end, I believe, for every person out there, there is a limit to how creative they can be. This limit depends on a lot of things, though. What the topic is, the detailed characteristics and traits of the person, their past and experience. And of course, there is some amount of shifting to your minds creative capability. People can learn to become more creative, or better said, learn to know their upper limits.
I think knowing oneself and how to approach your creativity is very important. That also means that you have to accept what this means to you and your work and the upper limit you can reach. There are always people who say you can do anything and reach everything - and of course, technical they are right. But if you, for example, are not a person with such a personality or ambition to reach goal number 5, then it will be quite difficult and you may feel more comfortable to accept that goal 3 is also fine for yourself. Of course, reaching goals has many more requirements - I just want to express that obviously not anyone will become the most famous person in area x out there for a rational reason.
That's at least how I think about it. This is a topic which can be approached from a lot of different angles and philosophies, so it can certainly be interesting to read other people's opinions on it.