I said time mattered. That means things progressed in the world, and time played an important factor in that.
At low levels, travel time was a big one. Players could go a month south to deal with Problem A, or they could go two months West and deal with Problem B, but they couldn't do both, because either problem would be dealt with (one way or another) by the time they completed (or failed) in their mission. Do you wait for your ally (but let the bad guy build up), or go in without his specialized help (especially if he has useful knowledge)? Do you wait out the Domination effect (which takes days), or go on and hope that it doesn't interfere too much? Do you go back into the Pit with less spells, or do you wait and let ghosts rampage the surrounding area?
At higher levels, temples needed time to be built, as did convincing large portions of the population in each and every nation to worship the gods again. A nation has to be run, including large troop movements, roads being built, and cities being reworked or built. The council of mages built its own tower, had its own army, and had to build political ties in all the nations.
They certainly could be easier to take out. And, no offense,
but your experience isn't universal, and just because it sucked for you when your GM screwed you, it doesn't mean that it works that way for everyone. I wouldn't do that to my players purposefully, and I'm sorry you've had terrible experiences like this.
Regardless of your terrible experiences, though, they don't apply to me. I don't run things that way; my players don't run things that way when they do run games. A "living world" isn't just out to make things more difficult for the PCs. You don't have to accept that, but you're simply mistaken if you think that it's somehow universal.
I'd call you wrong. But, I can't speak to "most games" any better than you can, really. So, maybe we should "call it a wash" instead? Because sitting here saying "my experience is that players get screwed every time when the world reacts to things" simply won't jive well with me (or other people like me), since it's not representative of my game in the least.
My players use the "living world" to their advantage more often than it screws them. Last session, they took some farms around a city hostage with about 100 people to trick 450 of the town's army out, then surprised the town's army by cutting their route to the city off, and attacking with a hidden force over twice their size. I didn't screw the players; they earned their victory. It was the opening salvo in what's going to be an ongoing conflict, and the other armies probably won't get tricked like that (the enemy army routed, so the players suspect word will get to the remaining areas).
On the other hand, they know that they can't just sit in the city forever and build up a higher resistance for the next few years. They know that the other armies will start to act, and they'll need to respond to it (and prepare for it). This might mean that they get hurt, but it might mean that they can prepare well enough to ready for the counterattack they know is coming (the question now is "when").
I don't know how it'll play out yet. We'll see. That's part of the fun. But, I'll tell you this much: my "living world" isn't meant to screw the players. Time matters. They only have so much time to raise more resistance fighters, move their army (or armies, possibly), craft weapons or armor, travel around themselves, etc. Time matters. It just does. And it's not to screw the players, it's because that's how time works in my game.
It's not just to screw the players. As always, play what you like