I’m sceptical. Are you honestly saying the events of your world happen independently of the PCs and you track what happens in each place irresepctice of whether the PCs are involved - which seems extremely labour intensive for little game effect.
Sort of.
I do precisely that for the limited region the PCs can access within a few days' travel. I do not do that for the entire world. That would be insane. I also fill things out as the PCs move through the world. If they pick up a job that takes them somewhere new, I fill in the world around them, just in case. I use wandering monsters to determine what random stuff they come across and then give those things details and integrate them into the world.
So the PCs are going south to a new place, what's east and west along their journey gets filled in as they move. What's there is then given goals and plans and set against the other things in the area. I randomly rolled two tribes of lizardfolk in a small area as the PCs moved somewhere else, so now they exist in the setting and the PCs are none the wiser. I don't go down to the level of naming everyone or giving them detailed backstories. Right now my notes on them are literally "Lizardfolk tribe A was pushed out of their swamp home by lizardfolk tribe B. Tribe A wants revenge". That's it.
But monsters move and migrate so other monsters will know about this and a rumor of the warring lizardfolk tribes may filter back to the PCs and they may engage with that hook...or they'll leave it and it will never be more detailed than that.
Or do you forgo event based encounter design completely?
Of course not. Events just aren't triggered by the PCs' presence.
If someone poisons the water supply the PCs can engage with that or not, at their pleasure. The water supply will not be poisoned when the PCs are fully rested, with nothing on their plate, and looking to me for the next bit of "content"...it will be poisoned with the faction that wants to poison the well gets to that part of their plan. There are other stages first. Consequences for the PCs not engaging will be fairly harsh though.
But the PCs entering a room doesn't trigger the monsters therein to spring to life. Or the PCs entering the square doesn't cause the manticore to get loose. If the manticore gets loose it's going to be when it can, whether that's midnight or noon...whether that's when the PCs are six blocks away or six miles. I don't treat the PCs as danger magnets.
I make use of a calendar and have things that will happen on given days. So, for example, on July 17th there will be an earthquake centered a few miles away from the starting town. What the PCs do in response is up to them. Where they are when it happens is up to them. When the calendar rolls over to that date I'll roll a random time for it to happen. So if the PCs are asleep, in the middle of a fight, far away from the town, or standing on the epicenter...it will exist entirely independent of their choices.