There has always been a sort of balancing act in roleplaying games, from the very first, though it went unrecognized then. In the games of Gygax and Arneson, the balance was weighted completely towards the referee; the DM had all the power to say yes or no to the players. Players were at the mercy of their DMs, who controlled every aspect of the game. If you asked your referee a question and they said no, that was the end of it. There was always, of course, some wiggle room for rules compromises, but in the end the final decision was left up to a ruling by the game's referee. In those days, it was implicit that the person running the game was someone that you could trust.
These days, there seems to be a highly adversarial relationship between PCs and DMs. I attribute this to the blowback of rules that followed years of subpar and downright poor DMs taking advantage of their position as ultimate arbiter to torture and violate their players. The relationship between players and their referee is a sacred one, one that is tantamount to that between a teacher and student or a parent and child. Abusive breaches of trust erode the power of the game and have resulted in a backlash of player-centric content.
What do I mean by player-centric? The first time I began to notice it was with the transition to 3rd Edition, though cries of foul play had been posted all over the internet even during the mid- to late-AD&D days. Players who were fed up with bad DM behavior enumerated bills of rights: their characters should not be killed off callously, they should be informed before-hand what rules were in play, basic things such as this. While I disagree with some of these so-called player's "rights," I understand the situation surrounding their genesis perfectly.
However, they have led to a balance of the game in the modern day where the DM has been stripped of most of his power. People are deathly afraid of railroading (being forced to do what the DM wants rather than what they want) which is not a consequence of the referee having too much power but rather of the referee being abusive. Players have also developed a sense of entitlement: they are entitled to the magic items they want, access to the character classes they desire, and all number of other things which they feel guaranteed to have. After all, the logic runs, we play to have fun, so whatever is fun for us, we are entitled to.
Yet, these players have lost the central tenets of D&D and let them be consumed by sheer masturbatory fantasy. They shift the balance of the game from being controlled by the DM (who must hold an entire world in his mind to let the players explore) to themselves. The game loses all vitality and meaning as it devolves ever away from the question "Did we win?" to "How hard did we win, and also how cool was it?" Removing the fear of death renders the game toothless, removing the challenge cheapens the reward.
There is very little respect for homebrew campaigns or DMs that run games left in the world. The most common phrase I hear these days is "I wanna play D&D... who wants to run it for me?" This attitude is indicative of the rampant disrespect that DMs garner. The DM of a 3.x or 4e game is expected to be little better than a computer, crunching numbers and following the hard and unbending rules of the game. God forbid they point out that even though the rules say you should have survived that fall from a magic carpet, logic dictates otherwise. Woe unto the DM who says "The ceiling has crushed you. No, we aren't going to roll for damage, everyone is dead." This is seen as an affront.
Players believe they are entitled to win, and to win in glorious ways, simply by the act of signing up for the game. They are hurt and feel betrayed when they are presented with problems that have no solutions, or enemies that are not carefully matched up against their capabilities to provide them with the illusion of danger but the reality of victory. It seems that what people as a whole are really seeking in D&D territory these days is a carefully balanced equation that simulates a rollercoaster: the emotional response of being out of control coupled with the logic that, at the end of the ride, everyone will get out safe and sound, content that they can ride again if they like.
That's not the D&D I want to play. That's not a D&D that respects the verisimilitude of the setting, or the work of the DM. If I wanted to ride a rollercoaster, I'd ride one; if I wanted to read a story about how some heroes succeeded, I'd read one. D&D must be surprising; indeed, to be worth playing at all it must not only be surprising but it must be in some ways a mirror of the world. It cannot provide themes and conclusions that novels can (not without badly forcing it to, perhaps at the whim of some monstrous DM like those the PCs of the late AD&D era railed against) so instead it must provide something even more like life. It is a series of picaresque adventures connected by no greater theme than the themelessness of life; playing D&D should be, at its heart, like the pointless exercise of living: you find your own meaning in what occurs around you, or no meaning at all.