Well, it is more of an issue because while 95% of things are challenge-worthy in Tier 1, it becomes 70% in tier 2, 40% in tier 3, and 10% in tier 4, maybe 1% in epic.
I've run plenty of encounters where a group of ogres see a party and run away, etc. when the see the party is riding phantom horses, has magical lights instead of lanterns, etc. which are obvious signs this
might not be a good idea. This is the hand-waving of encounters. Sure, they are there, but let's not waste time on them.
LOL yes, the 90% includes non-combative encounters.
Why should tier 4 be doing such things? I told my group how one time, just for the fun of a solo adventure, I ran a player whose character was an archmage, through the Keep on the Borderlands. As expected, he waltzed through the entire thing with ease. So, in an area with such a superhero, the heroes should have little if anything to do. It is far easier to help folk, get loot, etc. crushing low-level stuff, so why risk life and limb on the big things. Aren't there other tier 4 superheroes to handle it if it a world-ending threat?
I don't know how else to explain it other than for myself, I just find "over-the-top" sort of adventures too far-fetched for fun. I mean, with all the heroes in the world, how the heck did an army of giants ever even get gathered together? Were the current tier 3 and 4 adventures all just asleep at the wheel? If a rift opens and hordes of devils are coming into the world, wouldn't all the heroes in the area band together to stop it? Why is it the
party that has to do such things?
As to your point, yeah I completely agree. Actually, when I DM I find it refreshing when a challenging encounter is not so hard for my players, especially if they pulled out something cool or unexpected! Otherwise, if not special happened and I simply misjudged the encounter, it is a learning experience in balancing encounters vs. party strength. Such things have never bothered me, personally, but if a DM feels "cheated" because his hard encounter ends up being only easy, then he should re-evaluate his role as DM IMO. It isn't the DM vs the players, after all.