I think not only the Beginner's Luck but the main think which made profit is the fear of loosing the money. As so many times i have seen even now when ever i am betting with afraid of loosing the money in any new game in beginning i always winning but as the comfort level is going up or after 2 or 3 days play on 4th day it start to lose and until i find the reason i lost everything even the initial investment also.
So i think beginner luck is due to playing gambling in fear of not to lose the investment and that too playing without any strategy is giving profit but as soon as you start to use strategy and play and loosing starts it.
I'm not sure I can grasp how your fear of losing money can impact the probability of winning, but I agree that with a strategy you can lose much more than when playing without any. I think emphasizing the fact that beginners usually play without any strategy you are, probably, making a good point. Maybe that's how we can explain the so-called "beginner's luck", or at least partially explain it. Newbies play without any strategy and that's why they win more frequently than veteran players whose strategies kill their luck on a regular basis.
The more you fear the more you lose. Gamblers should gamble in free and clear mind and dont think too much about the result of the game. If you are lucky and experience your chances of winning will definitely increase. If you are new gambler you can try your luck only and should spend most of the time in seeking different techniques used by veteran players.