One of the curious attitudes on display on various forums is some resentment when a new or revised edition of a game comes along, especially if the changes are more than cosmetic.
I say it's curious because no one expects other products to stay the same from year to year. Everything from cereal to cars to cell phones are constantly being "new and improved." What not games?
Some folks seem annoyed that there's a new edition of Axis & Allies coming out shortly, so soon after the Anniversary edition. Yet the new 1942 edition is clearly aimed at a different market than AA50. The new edition is much less expensive and will probably take much less time to play as well. AA50 was definitely aimed at the true Axis & Allies fanatic. I doubt many copies were sold to customers who didn't already have a copy of some prior Axis & Allies.
Generally speaking I like to upgrade my favorite games when new and improved version appear. For example, I recently paid for new blocks and stickers for Quebec 1759 when the new edition came out. A nice service of Columbia Games is that they offer parts, so you don't necessarily have to buy a whole new game when they make a change. And they are pretty conservative with the changes, too. I'm still using the mounted Quebec 1759 I got with my 1970s-era edition, for example.
But even when the changes are enough to require a whole new game, it can be worth it. For example I bought the Jutland edition of the Great War at Sea series when it came out, even though I already had its Baltic and North Sea predecessor. I did the same things with Bitter Woods. I sold off the old copies, but sometimes I keep the old version. Probably the best example of that is the game Napoleon, where i kept my old Avalon Hill versions even after I got the Columbia edition. I thought the changes were significant enough in that case that it was really two different games.
But often I also elect not to try to keep up with game system. I've bailed on the Down In Flames series, for example, even though i have quite a few parts. One has to draw the line somewhere. But I'm satisfied with what I have of it and I'll probably keep it because there's no reason why I can't keep playing with it. It's not a game I'd play in a tournament and it doesn't hit the table too often at game clubs, so the only time I'll probably play it is with some friend. And for that purpose it won't be obsolete.
And that seems to me to be the bottom line. I think everybody probably has maybe a dozen or at most two dozen games/system they can keep up with. Those favorite/popular/tournament games are worth keeping up with, but should be focused enough to stay within whatever budget you have. For everything else, so what if there's a new edition? Unlike a VHS tape or a Nintento cartridge a good board game is just as playable with your friends no matter how many new versions are out there. Indeed. I know that many Cosmic Encounter players didn't even bother with the Hasbro/AH edition because they thought the earlier Mayfair edition was better.
Few modern games are as stable as something like Chess, but then the era of innovation for that game was a few centuries ago. Maybe some of today's favorites will settle down in the future.