If every time you thought about doing something you dreamed of you just did it instead, you'd probably be a master at it by now.
Think about all of the times you wanted to learn a musical instrument, a new language, or get in shape. Think if all those times you wished you were an amazing guitarist or were in excellent shape, you practiced or worked out?
The problem is, most of our brains are programmed to respond to instant gratification. So, the long-term goal of working out doesn't really register in our minds. We think that eating a brownie now or some pasta isn't going to hurt our long-term goals of looking like Zac Efron in Baywatch. But it totally does. However, if you want proof that progress is possible through practicing daily, then just look at the work these artists are putting out.
Some are a long time apart.