Immersion is different for many people. If I’m a player in a game and decide to have my character leave a city, and everywhere I go, I keep hearing about what’s going on in that city, there’s a good chance it has the opposite effect… that I’ll feel like I’m being chased by the GM’s plot. Which doesn’t evoke a “living breathing world”.
Obviously this may not always be the case. It depends on many factors. But I don’t think that we can chalk all this stuff up to immersion.
Putting aside the hyperbolic example, the
living breathing world, as I understand it and implement it, is meant to evoke the changes that might naturally seem to occur within a passage of game time, accounting for
DM solitaire as well as the consequences (good and bad) of past player actions. One may also be using a published setting calendar or AP, as the campaign may have been set in a certain time period and thus certain known events occur.
Changes can also include colour.
The whole idea is to keep or help maintain the players within the headspace of the fictional game (
immersion), offer reasonable outcomes, sometimes even predictable outcomes for what has already occurred within the campaign and possibly build future hooks. These hooks can be storylines for the party as a whole or to be individually explored by the characters. The latter could relate to character's backgrounds or desires.
This concept is used in Trad games but it can easily be incorporated in games where players have some level of creative input. The way I view it, the
living breathing world is an exercise within the exploration pillar.
That's my take on it. I don't know if I did the concept any justice - but yeah, I do not think it is a difficult idea to grasp.