It depends on how you look at it. Most of the writers and authors are or were quite successful in life, I don't need them to show me telekinesis abilities. That's a very specific area that doesn't have much use in life, other than improving your focus. Trebor Seven uploaded a video last month, and even he said that he had stopped doing it for 9 months, and focuses his energy on other important things instead.
Being able to see/sense/guess the correct roulette numbers requires a strong belief that you can do it. It needs to be gradually increased. As a beginner, no matter how hard you try to tell yourself that the next number is going to be 16, deep down you don't believe it. And as soon as you have the slightest doubt, you are more likely to fail. And the more you fail, the more you doubt yourself. That's why it's hard.
Yesterday I had a pretty bad day, I couldn't stay focused, I saw several numbers, but didn't know which one to bet. I only hit one number, so after a while I started to lose my faith. I even tried to manifest a number again with a 20 minute meditation, but I was already in a bad mood, and I only hit a neighbor. My number never showed up.