There is something I don't understand in what you're saying.
I wouldn't want to make a strawman here, but it seems that you are concerned about difficulty for difficulty's sake alone, while (at least I) approach it as a 'means' towards whatever goal the game has… I can completely agree with you where the games where the goal is the difficulty are concerned (as in Wiz4) but I don't agree that that's the only case (in the article that this thread is about the writer doesn't seem to think so: I understand that he considers pacing to be a more critical aspect of his work - and that's perfectly valid for me)
No, my concern is how developers today are very focused on optimising their designs to match the perceived expectations of their audience.
They know that people want the freedom to choose how difficult a game should be, so they need to design their games so they can implement multiple levels of difficulty without it being too expensive or time consuming. Like Oblivion, where everything scales and the "difficulty" is completely superficial and rigidly simple.
So, they end up simplifying mechanics and gameplay to an extent - and the players end up having to "guess" which experience they should have when playing.
"Do I need easy or normal? Hmmmm."
"I'll try normal and set it to easy at first obstacle."
They don't really make the investment to overcome the challenge if they know they can just reduce difficulty.
Like, in Demon's Souls, if you had the option to circumvent the harsh death penalty, most people would do so - because no one likes to run through the level again.
People think that kind of freedom is what makes for the best experience, and I don't.
I don't think it's a good area of focus, and I think developers should concern themselves ONLY with the "pure" experience.
If a game should have a harsh death penalty, then make it harsh. Don't let the players choose - because the players aren't artists. They're players.
I want the art to go first, not the business.
If a game is good, players will adapt.
Just like an "art" film can be uncomfortable or challenging to the viewer - but that's what it requires for the vision to be intact.
I don't like to think of games as a business, even though that's what it has become.