Well, there's been an evolving difference in how "D&D" is assumed to work. Consider these assumptions about the role of the DM:
(1) The DM creates an environment and impartially moderates interactions within it. If the "playing field" as a whole is much too difficult or too easy, then players are likely to lose interest. However, within the range provided, it is up to the players to seek their desired level of risk and reward.
(2) The DM creates a series of encounters "balanced" (according to rules) against a party of a given number of characters of a given level. It is now (at least primarily) up to the DM to determine what players face, so where does strategy come in? It comes in with "builds" -- and the situation can start to look like opponents spending points and looking for loopholes on army lists before a war-game tournament.
(3) Players reject the the designers' suggested range of encounter difficulties -- especially the provision for those that are actually very hard (and thus unlikely) to beat. The view gains traction that players triumphing should be the default, not an outcome in doubt without players stretching their skills. The DM's role thus becomes one of extreme partiality in the players' favor. The rules get redesigned to minimize variation in outcomes due to variations in player skill, and to increase predictability overall. Now, it may not be enough for a DM even to have set up a "fair" encounter if the outcome is a setback for the PCs.
Here we are passing out of the realm of game and into the domain of illusion, the appearance of game for the sake of theatrics (like a casino set on the stage of a James Bond movie production). It's not an instantaneous change of state, but rather a gradual slithering across the threshold, and it is not yet complete.
(1) The DM creates an environment and impartially moderates interactions within it. If the "playing field" as a whole is much too difficult or too easy, then players are likely to lose interest. However, within the range provided, it is up to the players to seek their desired level of risk and reward.
(2) The DM creates a series of encounters "balanced" (according to rules) against a party of a given number of characters of a given level. It is now (at least primarily) up to the DM to determine what players face, so where does strategy come in? It comes in with "builds" -- and the situation can start to look like opponents spending points and looking for loopholes on army lists before a war-game tournament.
(3) Players reject the the designers' suggested range of encounter difficulties -- especially the provision for those that are actually very hard (and thus unlikely) to beat. The view gains traction that players triumphing should be the default, not an outcome in doubt without players stretching their skills. The DM's role thus becomes one of extreme partiality in the players' favor. The rules get redesigned to minimize variation in outcomes due to variations in player skill, and to increase predictability overall. Now, it may not be enough for a DM even to have set up a "fair" encounter if the outcome is a setback for the PCs.
Here we are passing out of the realm of game and into the domain of illusion, the appearance of game for the sake of theatrics (like a casino set on the stage of a James Bond movie production). It's not an instantaneous change of state, but rather a gradual slithering across the threshold, and it is not yet complete.