There is various properties that affect price.

If there is less of something- meaning it is high demand since there is barely any of it. For collectors the price rise. It does not matter how good or bad the game is.

If a certain person work on the game- Like programmers, actors, artists, commedians, polititians, writers. Generally somebody who has alot to offer or is already famous. Like if Mcheal Jackson made a game on any system they would instantly be worth gold. That plus his sig or kiss mark would be plasma.

If the game is fun to play by many people- like somebody played something and will give a huge load of cash just to play it again.

You have a memorty or memories tied to ceratin game objects- Like I played this or that or sawed that in a store and want to buy it.

Generally it depends on popularity and intelligence. You also have to conisder a job is a job and the people who work on this just consider it part of what they do and nothing special.