Not only is this boring (it gives players less opportunities for making high-stakes decisions during the fight) - it also makes it harder on GMs to balance encounters.
If you let players and enemies decide to flee or negotiate at any point - the encounters can be much more deadly without turning into TPKs. Players now have more decisions to make on each round (and they can debate during the fight if they should run or not - which is a potential for great roleplaying moment).
And when they decide to run - a successful retreat is an interesting tactical challenge by itself allowing players to use abilities and combos that they seldom need during traditional fight.
One of my favorite moment of roleplay was when our barbarian was arguing with our curious druid whether to check out a very sketchy haunted manor. Eventually they went in and there was a huge battle, druid (against the rest of the team) poured blood into a well and a demon appeared. Half the party started running, other half was fighting with the demon minions, the demon started bargaining with the druid for his soul, barbarian started to run but after 2 turns turned back and tried to fight the demon while the rest of the party also went back and disabled druid to save him.
Eventually the party escaped from the manor (killing the demon was out of the question, it was obviously too powerful).
Our DM was always telling us he never balances the encounters - it's on us to escape in time :) And there were MANY dead PCs. Some players were on their 3rd character by the end of 1.5 year campaign.
Resurecting a dead PC was a major plot point - we had a noble lady from one of the most important NPC noble houses in our party, and she died. We tried resurecting her, but one of the players had to sacrifice something (we rolled d100 and only that player managed over 95, to persuade the god to resurect the character he had to promise to become a priest of that god - and he did multiclassed because of this). The god was basically Loki, and he tricked us - the player character was ressurected as undead :)
Fairly solved problem outside of DND tbh.
Yes it's easy to fall into the traditional boring "here's 5 orcs, now fight to death" trap, but it's more about the D&D culture than about the system itself.
D&D wasn't my first system (it wasn't popular in Poland - we mostly played WFRP) and I certainly did fall into that trap a lot early on.
I cant comment on Warhams but other RPG's I have played dont really care about encounter difficulty. And I am not even talking about narrative only stuff. But even savage worlds I can go and find 10 wild cards or 20 wild cards or come up with almost any Ace, and its just a matter of player approach as to whether the encounter is difficult or simply deadly. To really create a TPK situation you would need to design enemies specifically to do that.