Most games that have ever existed were designed around a fundamental concept: a fair competition on a level playing field. They existed almost universally for thousands of years as an entertaining, fun, competitive activity. There was nothing equitable to a "gear treadmill" or "power creep". In fact, the idea that someone in the game would have a significant artificial advantage over other players, or over the materials that served as the playing field, would be contradictory to the fundamental concept of a "game". Even most video games do not employ power creep or vertical progression.
Yet, the MMORPG genre is comprised almost exclusively of games that employ ongoing power creep and gear treadmills, even though there is nothing inherent in the concept (or even the name) of the genre that implicitly or explicitly refers to vertical power progression. I will agree that the roots of the genre - fantasy role-playing - did employ some limited power progression, but that progression was hardly the defining characteristic of the genre. The changing, fluid interaction of game-master created environment, including clues, puzzles, and conflict, vs the intelligence, wits, and luck of the adventurers in meeting interesting and challenging environmental goals and problems more defined the Dungeons and Dragons concept than what is now simply a gear-grind for it's own sake.
For whatever set of reasons, the concept of a gear-grind power creep took hold in the MMORPG genre and essentially took it over, to the point that those who play, and those who develop games for the genre, apparently cannot even imagine an MMORPG being successful without it. We're all familiar with the term "content locusts" - players that consume vertical progression in a game and then either complain that there is "nothing to do" or move on to other games. Developers often attempt to keep up with vertical progression content locusts by churning out more vertical progression every few months.
Obviously, thousands of games have been successful without power creep or gear treadmills. People pour millions of hours and billions of dollars into games that have no power creep gear treadmills. So why the myopic and obsessive focus on that particular mechanic in MMORPGs? It's obviously not necessary for a game to be successful, and you can make a pretty good case that it drives a lot of potential customers away for many reasons:
1. It destroys any sense of "fair competition" between players.
2. It "forces" players to do things in the game they do not want to do (hence the term "grinding") in order to stay competitive.
3. It forces players to play the game as if it were their primary job in order to stay competitive.
4. It funnels game structure and design concepts down a very narrow path, basically making the game all about the grind, regardless of what else is offered in the game, which is psychologically off-putting for players that don't want to grind to stay competitive.
5. It biases development time towards trying to keep content locust type players satisfied, which is off-putting for those who are not interested in grinding.
6. It ruins many other potentially profitable and fun systems thout could be in such a game, like WvW or PvP that is competitive from a player skill point of view.
I'm not saying that developing a game that serves the content-locust mentality is a bad thing, nor am I arguing that being a "content locust" is in itself a bad thing. All I'm asking here is: Why is the MMORPG genre so obsessed, from a producer/developer standpoint, with a game mechanic that is a very marginal concept when it comes to the gaming industry as a whole, when there is absolutely no such limitation/focus inherent in the concept of an MMORPG?
It's like the genre has put itself in a power creep/gear treadmill straightjacket for no good reason and cannot conceive of anyone that wants to play an MMORPG without the strraightjacket on.