Previously I was sure that you conveyed the opinion based on common sense and rational thinking, I agree with what you said and I think the idea of becoming a professional in gambling is something that sounds unreasonable, the reason is clear as you said that gambling is an activity that is quite dependent on luck, or although there are indeed several types of betting activities that can be done by applying skills and analysis but still luck is always the most important factor to confirm victory.
This means that there is something that a gambler can never learn, namely luck, because no matter what we will never know how to control luck so that it always sides with us, meaning that of course defeat will always be a certainty, and I think it makes no sense to set a goal of becoming a professional in a profession that in fact cannot be learned.
Your submission is absolutely spot on if you ask me. It's over a decade I started gambling and I've taken my time to study gambling and how it works which is why I can't be easily influenced into doing anything I do not want to do. Gambling to me should never be seen as a means by which anyone can earn a good living out of it because I've seen people who threaded that path and I also saw where they ended. Like you rightly said, a gambler can only make predictions based on his his experience about whatever he's gambling on and his belief of what is likely to be the possible outcome but he's not just but doesn't have any control of what will be the final outcome. Gambling is mostly influenced by luck so making it a professional engagement is not a healthy idea and the end is always not good