Well it's not 50/50 a lot of people lose and only a few people end up profiting from casinos so the money is transfered to the casino and not the lucky players most of the time.
No, but the chart seen in the first post is totally possible.
There will be a group of gamblers who will always lose, and one that will always win, but the member of that group will change every time, like a shuffle.
Of course the mean is always people that mostly end up breakeven or will little losses.