I've never seen a 4th ed combat where it actually takes 2 minutes to determine and resolve an npc/pc action.
Never? Ever? You remember all 5,000 actions that have occurred in 100 encounters? You have never had a slow player in any of your games, even from a hangover or a real life distraction bothering that person?
Nobody who was scrambling and looking through their powers to find one that might help, just because an moment earlier, the entire encounter went south and the PCs are now desperate?
Resolution is typically fast, but determination can be dog slow depending on the person and the situation. And even resolution can be slow if the player forgets some modifiers to the current situation "That's 17 damage. No, wait, wait. The Bard added 2 more. Do I get the 3 for the Cleric, or is that only if I have combat advantage?". I've had situations where the player doesn't quite know how his or her power works and the character sheet is passed to me for adjudication. That too takes time for a turn.
I've seen combats where it takes that long because we are chatting, socializing, etc.. but my gaming groups also using gaming time as our socialization time because that the only time we get together, most of the time anyway.
When I've seen it done and run combats myself where there is nothing but concentrating on the task at hand the combats go pretty darn fast.
My experience that all combats have chatting and socializing. Socializing is one of the reasons most people play the game.
But, the socializing is not "telling long stories about what happened that week" which does take up a ton of time (we reserve most of these to when the players first arrive at the game). It's jokes about the current situation. It's comments about the food. It's minor conversation that does not significantly prevent someone from rolling dice, or adding up totals, or placing a bloodied token on a miniature, or whatever.
But when the groups I am in are in combat, they tend to be somewhat focused on the combat. Travel and roleplaying and out of combat situations are more freeform. Combats, except for the jokes, are typically business at hand.
Concentrating on the task at hand making the combat go fast is also dependent on the players and the PC resources. With 20+ options at level 26, there are players who slow to a crawl with that much information to process, even if they are familiar with their PC.
I have a player who occasionally says "Ok, I used a move and a standard, let me see if I have a minor I can use". When she does this, I give her 5 or 10 seconds to look through her character sheets, even though I pretty much know that she won't find anything since her minor action powers are for the most part pretty obvious when applicable.
I have a player who just started 4E two months ago. She could be really slow being so new to it, but as it turns out, she is fairly average for our group.
It's all dependent on the players.
Yes, two minute individual turns are not unheard of.