Personaly, I think 99% of people can be a pilot of some sort given the time and mainly money. I have met people that most people would advise to give up before they even started but still made it to their PPL but took an awful lot of hours and money.
Some people are capable but just too lazy to put in the work. As with anything there are fears to get over and skills to learn. Most people can learn skills if repeated enough but some take much longer than others. Most people can get over their fears if, again, they do things enough times to begin to have trust.
Making it to a professional pilot is even a bigger task and to do it, you really do need the dedication and again money. For most people, including myself, it was money that made me stop at PPL.
Believe it or not, I was terrified of heights before I started my PPL and it's something I had to conquer, but it was something I always wanted to do despite that phoebia so I put in the effort required and found the money. I am still scared of heights, but that dissappears when I am up there and it doesn't even enter my mind. If I fly on a commercial aircraft or look out the window on a tall building then that fear comes back but I have learnt to trust being in a small, simple aircraft.