FreeKaner
Prophet of the Dumpsterfire
I will clarify what I meant by arbitrary - having freedom to choose whatever you want in the world that is limiting potential choices. An engine example is good to present this concept at basic level, when we have objective physical limitations. Projecting of RPG has less boundaries and that fact could took as too pure idealistic statement that "everything is possible in projecting RPG" which I disagree. But we're getting possibility to reshape many things in abstract reality of gaming mechanics as long we understand how this abstraction works on its internals rules.
In simpler words - We are forced to live a life and this life is forming our shape as people and creators.
I understood what you meant but there is obviously a language barrier.
People's experiences are also not necessarily good, because a game works best when its mechanics and setting work together as well, those are also often made by different sets of people when video games are involved. Gameplay is also a vehicle to deliver the narrative and setting. Gamedevs of course have to make sure their game fits to the ruleset when they adopt the ruleset from somewhere else.
Good settings will be consistent, and indeed the concept you are talking about is called internal consistency. However that is not enough, great settings will not only be internally consistent, they will also process themselves befitting the philosophy of the setting.
That's why Lord of the Rings is a good setting for example, Tolkien being a Catholic in England and someone interested in linguistics, mythology and history of Anglo-Saxons had the right personal experiences to create a fantasy setting but also created a very consistent setting that has central philosophies that are worked throughout the series.
Another setting I like is Warhammer, one of the reasons why I like that setting is because the creators of that setting obviously read primary source material from the era they parody. A lot of the fluff in their setting is written with the language and mannerisms of how people wrote things in 12th-17th centuries with additions from 19th-20th for 40k. It is a setting that is meant to be absurd, but takes what it does seriously at the same time.
Engine comparison doesn't work, because engines are generally not made with personal preferences of engineers, they are made with what's available. Still it is true that limitations, and even arbitrary ones are actually good. Making things within constraints actually stokes creativity, absolute freedom is not a good quality in any creative endeavor. Consistency is constraint in itself.