I believe there is a 50/50 relationship between the player and the instrument. Guitar as a popular instrument has had many differing approaches to technique. When I was working on a BA of Music in college, I never heard the violinists in the legit program complain about their instruments. Not that all violins are created equal or are not precision instruments (they certainly are), but that the violinists train to master a precise technique. This way, there are clear expectations for the instrument and also the performer. These folks are professionally trained in a tradition steeped in history. They have already decided basically what a violin is and does.
Most guitarists on the other hand, play a style that evolved recently compared to classical music, with new techniques and not as much formal training. Since the expectations for technique are not clear, the expectations for the instrument are not either (although I must admit that this is part of the allure of guitars and their music, the charm and character!).
Some folks play so lightly that they cause very little excursion of the string. If the string doesn't move, precision fretwork isn't really necessary, at least not for the player (but possibly for the guitar) and especially if they don't play more than open chords. Almost everyone plays harder than these folks. Some super light players are timid newbies, some have disabilities or injuries that limit a more forceful technique, some just like to play lightly.
The other end of the spectrum features folks who hit hard with high action. When action is high beyond the possibility of ringing out at the next preceding fret towards the bridge, precision fretwork isn't necessary (even though the guitar could be improved with it). A side effect of high action can be less precise intonation.
Some folks just hit hard and push the string into a greater excursion than the action they have chosen will allow. Precision fretwork is wasted here because the player's technique over rides the action of the guitar anyway. This is sometimes the repairman's dreaded "I want low but no buzz" action customer, the person who wants to have .009s and on the deck action but proceeds to smack the guitar ala SRV and then complain about the guitar. To paraphrase something Joe Glaser said to me once, “I guarantee it will buzz,” meaning that any guitar can buzz if the string is set into great enough excursion. This is why I do set up work and take in leveling and refrets by appointment; I want to see how the player approaches the instrument and what he/she feels the problem is.
And I think it can be truly stated that every guitar buzzes to some extent. After all, it is a vibrating string held against a metal fret. In the case of steel strings, its metal on metal. On most electric guitars its a metal string on a metal fret and a metal saddle. Metal on metal sounds buzzy. This is the nature of the beast, the price of the charm of the plucked, bent and slurred string and what differentiates guitars from pianos. When folks describe a favored guitar as playing with no buzz whatsoever, perhaps it would be more accurate to say that the particular guitar doesn't buzz when played a particular way with a particular set up. The job of the player is to play the guitar that particular way and for the guitar to have that particular set up. I see my role as helping the two to meet in the middle and work together.
Another factor to consider regarding buzzing is that a string doesn't "ring" or rotate in a round pattern, but rather an elliptical one. And as such, an ellipse has one point of travel greater than the others (compared to a circle with its all equal radii). And if the player strikes the string in such a manner that the furthest travel of the ellipse is perpendicular to the fret tops, the string may buzz for this player, when it will not for a player striking the string another way. I see this most with folks who seem to get a large portion of the flat part of a pick to strike through the string parallel to its lie (interesting Frank Ford article on this topic: http://frets.com/FRETSPages/Musician/GenSetup/InYourHands/inhand1.html).
Two other interesting observations in my mind are when a string is struck hard and the axis of the elipse rotates towards perpendicular with the fret tops so that the initial attack fo the string doesn't buzz, but the sustaining note develops buzz, and when a string is first struck, it experiences a "shock wave" before settling into the elliptical pattern. All of these things can be controlled through technique if the action and relief curves are in the desired alignment. If technique and action do not compliment each other in this instance regarding amount of buzz or string noise, then perhaps a higher action is required.
I have seen examples of bad strings and saddle imperfections causing buzzing. Time to change strings, sometimes production runs or brands and deburr saddles, check for loose screws and hardware.
Occasionally there will be tortional influences on a string that cause it to buzz in excess no matter who plays it how. In this case, it is out of the purview of precision fretwork as it is related to breaking angle, string length and hardware.