Interesting premise, and a few years ago I might have agreed wholeheartedly that modern gaming is pandering to the masses and has become too easy. But then along came games like Dota 2, Day Z, Dwarf Fortress, Path Of Exile, and Dark Souls. The learning curve to not embarrass yourself in a public game of Dota 2 is probably around 100 hours. It has some fiendishly obtuse rules and requires split second reflexes as well as in depth knowledge of the metagame as well as deep domain knowledge of the item tree and hero skills. And it is by far the most popular game on Steam right now, with over 400,000 concurrent players online some days and over a million logging in each month, not to mention a very active competitive scene. Path Of Exile has proven to be a very successful action RPG where the most respect is earned by playing "hardcore mode", that is reaching the endgame without a single death. Speaking of permadeath and difficult games, look at DayZ. No instructions, no tutorial, permadeath, weird bugs and glitches, dropped in an open world military sim with zombies running around and the map is in Russian. That's pretty difficult, and it was a smash hit. It's similar to the resurgence of other roguelikes such as Angband which feature permadeath, arcane key mappings, minimal curses style GUI with primarily ASCII graphics, and successors such as Dwarf Fortress. Oh, the author wants to talk about difficult platforming games on the console? How about Super Meat Boy, which offers all the platform challenge of the yesteryear classics. Shmups? Check out Really Big Sky and Sine Mora. There's plenty of great, challenging games out there today if that is what you are looking for.
DotA 2 is somewhere between Crack Cocaine and Heroin on the addiction scale. The other side of DotA's learning curve is that apart from being steep, it is also very deep: you can STILL learn so much more at the top skill levels because the game space is so large and unexplored.
I personally ended up building some custom Markov Chain Monte Carlo models (because with the Steam API you can pull a lot of match data) with shared priors just to understand the farming/win relationship per hero (and you need hierarchical Bayesian models because with 100+ heroes, 10 heroes per game, and needing to account for between-hero relationships, you run into the curse of dimensionality quickly).
It's almost more fun to analyze DotA computationally and watch tournaments than to play it (I watch more than I play). That's a truly ridiculous skill space and I could probably do an entire PhD's worth of statistics mining just off DotA 2.
I think that improved design has made it possible for many modern games to ramp up difficulty. One of the reasons that Super Meat Boy gets away with its fiendish difficulty is the incredible fidelity of control that the game offers. When you die in Super Meat Boy, it's never the fault of "awkward controls" or the "weird physics" (two complaints common for many primitive platformers); responsibility for Meat Boy's death lies solely with the player. The same is true of Dark Souls, where everything about the game from its combat mechanics to its level design affords an immense degree of player agency. Previously, some games had to be more forgiving to make up for shortcomings in game design.
Nitpick: DotA has existed for a while now, nearly 10 years.
I remember playing the imbalanced 5.5x versions somewhere around 2004. The modern versions of DotA were the 6x, started in 2005, and they are basically the basis for all modern DotAs (Heroes of Newerth copied heavily the map layout and some of the heroes ; it was pretty successful until DotA 2 came out). DotA 2 is basically an engine overhaul of DotA.
Roguelikes are even different: Dungeon Crawl Stone Soup is known to be hard to win but easy to play. It has tutorials and a hint system. They're aiming for zero need to read online guides. Compare that to Nethack, which is chock-full of weird stuff that you have no hope of discovering on your own.
Having won both I think that the only real difference is DCSS takes such a ridiculous amount of time for a 15-rune win that you just don't care by the end. I felt like I had to go through the same amount of spoiler reading, overall. And both are easy once you have a solid build strategy.
Have you played Brogue? That is really something special. It's a really stripped down game inspired by the original Rogue. There are no classes, so your build depends on the items you find. Rather than experience points, you'll find a finite number of scrolls of enchantment to spend on items. The tight food supply forces you to descend, which in turn prevents you from saving scrolls of enchantment for too long because you'll need to spend them on your items to survive. But the longer you can delay the better, because if possible you want to spend them on top-tier items.
(I haven't played DotA 2 but I've played DotA and Heroes of Newerth
Almost all of those things are examples of a game (DotA 2) being hard in a bad way/for the wrong reasons. The hallmark of game design is that it should be easy to learn but hard to master, but DotA games are notoriously hard to get into because of the steep learning curve, mostly because of all the dozens (almost 100?) heroes', their abilities and all the items (some of which have active/spell abilities) that you have to learn. I was useless in all of the initial games that I played in HoN, even though I had friends to help me. I still get bitten in the ass by not knowing all the abilities of some hero, or the fact that he has some item that totally negates one of my heroes strengths.
Strategy games of any interesting complexity usually have a steep initial learning curve, where you'll fuck up everything in the beginning and/or get killed by overlooking one single aspect of your base management or army control. But DotA is astonishing in that it was created in a game where you have to control up to three heroes, an army and base management, simplified it down to controlling only one hero - and made the initial learning curve of the game harder than the original game (Warcraft 3)! And this custom game with the higher barrier to entry in the end eclipsed Warcraft 3 itself when it comes to popularity!
