Some people really do believe in beginner's luck. Although that is just a superstition and a coincidence mixed together. But there's actually no harm in trying in believing in it. What's destructive is one's action after achieving what he want after trying. This is often the trigger to be greedy. Some people tend to want more even if it's already beyond what they can handle, hence they end up losing.
It's still a matter of discipline. Let's not blame gambling or advertisements because after all, we still have the freedom to choose.
There's an explanation for that occurrences, Typically newbie gamblers don't feel fear and risk of losing when they start playing that's why they can decide freely and control there bets properly to some extent. A positive mind usually come up to a positive result. Problem will aris when newbie start to feel the fear by encountering lose streaks. At this point, They will lose self confidence and always doubt on the result which makes them uncomfortable on betting. They usually want a fast game to quickly to recover loss or exit on the fear pressure.
There is nothing like beginner's luck, I agree with that. I also do not think every newbie gambler does not feel the fear and risk of losing everything. There may be some newbies who might come with that attitude and most of the time they are the ones who lose more. The whole game depends on probability and how the game developer has implemented it. You can control the outcome to an extent but you cannot prolong it. This is why you need to know when to stop and when to continue.