how do you actually know you "slowly getting there"? how do you measure that? and IF you can measure and know what it means to "already be there", wouldn't you actually... be there?
A lot of our behaviours and responses are driven by subconscious habits and thoughts. I may know that I have a bias towards doing X, but that doesn't mean that I consistently avoid doing X - in fact, quite the opposite. It takes years of re-training your subconscious to get away from behaviours which have become habitual. Knowing the way and walking the way are two different things, as they say.
I know I'm slowly getting there because I can observe the direct correlation between how I've shifted my thought patterns, and how the situation around me has shifted. One could posit coincidence as an explanation, and that may be true, but the areas of my life where I don't apply this "growth" mindset are the ones that haven't grown. Try it for yourself and see if it does anything for you.
Another example, with contrast between areas where I'm applying the mindset and those where I'm not: learning. In my work, I've blown away the excuse that "I don't have the time to learn" - I was lucky that the circumstances forced me to. As a result, I am now basically an expert on tax credits and grants, and adding more similar fields as time passes, without any hesitation.
Conversely, I've had a "I just need to get things done" attitude to programming and fiction writing over the last few years, and those have budged little if at all. I know that's the wrong mindset, but it takes time to get over it.