...for you, what's really at stake?
I'm going to take this a slightly different route than most people seem to be (and I apologize if someone already made this point, but I only read the first half a dozen pages or so of this thread...).
At the heart of the edition wars lies the future of the gaming industry. The success of 4e determines the path of the D+D brand, and steers the future of the entire hobby has we know it.
It is an undeniable fact that D+D (and, by extension, WotC) is the biggest name in (tabletop) RPGs. Ask someone who has never played D+D if they've heard of Pathfinder or OSRIC. They haven't. Some may have heard of Vampire or Warhammer, but it's pretty much guaranteed that everyone who has played those games has at least experienced D+D at some point in time. The bottom line is that D+D is the de facto standard brand when it comes to paper-and-dice RPGs.
It is a slightly more deniable fact that RPGs are not as big as they used to be. The market is smaller than it used to be. Gamers are lost to computer games, CCGs, or just plain don't play paper-and-dice games as much as they used to. The numbers behind this fact are hard to find, but it has been discussed in other threads here and I generally believe it to be true.
Another unfortunate fact is that D+D now has a smaller market share than it once did. When D+D was the only game in town, it supported (barely) a ridiculous number of expansion packs and settings. It now has to compete with Paizo, White Wolf, Warhammer, and countless other games that nibble away at it's market share.
After losing all of this ground to other media and other manufacturers, D+D is doing it's best to get by. And D+D gets by by selling books. And it doesn't sell books if you're not buying the current edition.
So what happens when more people are playing out-of-print versions of D+D than the current edition? WotC stops being the biggest player in the RPG world. What happens to the market when the flagship product isn't the flagship anymore? I honestly don't know. Maybe Vancian magic makes a comeback. Maybe miniatures take over. But you'll stop worshiping Vecna, won't fight any more beholders, and won't run into Elminster anymore. The world won't end, but it changes a lot. The hobby as we know it doesn't die, but it changes form. And, oddly enough, that's what most people who resist new editions dislike the most.
The closest analogy I can think of is the history of the arcade. If you went into an arcade in the 70s and early 80s, you would see a mixture of electronic and mechanical games (i.e. pinball). Flash ahead to the late 80s and 90s, and you would see that the arcade cabinet has become pretty standardized in terms of controllers and overall design. Arcades were a common location for new games to be released before they went to consoles (sometimes not being released until the next generation of console due to hardware limitations). Fast forward to today, and you will find almost no standard cabinet games left. Every game has a customer controller (a gun, a guitar, a dance pad, a steering wheel, a seat, etc). To stop their losses to the home video game market, arcades have evolved into the games you can't play at home.
The arcade is still a fun place to go. But there's a lot less of them these days. And if the only things you want to play are pinball and Robotron, you're in for a search to find what you want.
Not worthless. 
