Volumes have been stated on this matter, and the bickering and disagreement about where the "hot" slot machine games are installed in the casino are still on-going – over sixty yrs after slots were first placed in gambling houses.
The standard rule is that the best slot games were put just inside the main foyer of the casino; so that potential gamblers passing by would see actual jackpot winners and be enticed to come unto the gaming floor … play. Our perspective is that this is not so anymore.
The majority of the large casinos presently are oversized complexes and you no longer can see inside from the sidewalk, so there’s no longer a reason to position the ‘loose’ slots near to any doorways.
Another classic rule is that loose slot games are installed on the major aisles inside the casinos, again so that more persons could see winning jackpots and be inspired to play. Notably however, we find that this also isn’t a universal rule any more.
What casinos found over the years is that people walking down the busy aisles were frequently on the way to somewhere else. If they played the slot machines at all, they would simply put in their loose change because they happened to be walking by. Win or lose, they would very often not stop to keep playing. And the last thing a casino wants is for someone to win a jackpot by playing only a few coins and then not stay to put it all back in!
In recent times, casinos are constantly changing their perspective about where to place the loose slot machine games.