Bill Zebub
“It’s probably Matt Mercer’s fault.”
In my experience, lore only matters for players, if it becomes relevant to their decision making during playing the game. Anything else is fluff that rarely becomes of any relevant meaning to the players.
Absolutely this.
Too often GMs, or adventure authors, indulge their desire to craft a whole backstory for their world, and expect the players to understand some part of it.
The only way I've seen lore/backstory work well, which includes the players being able to remember it, is when the bits and pieces emerge because they are immediately relevant to player goals.
I'll add that the same is true for lore intended for the GM in adventures/settings: too often the very first section is the history/backstory/lore, with the implication that the GM needs to understand all this stuff. I hate it. I want to know the state of things in the present. All that lore and backstory can be put into an appendix, if it's necessary at all.