I'll start out and say that this piece is purely from an armchair executive point of view. I, honestly, have no idea how to run a very large corporation, and my education and experience is placed well into another industry. But lets role-play for a moment. If I were in charge, one of the biggest things I could see supporting is the release of content from prior editions. This also includes the design and development of --new-- content utilizing DDI's medium. This means that the company can support all different editions with minimal impact to their current brand. They already own the copyright to the material, why not stir up some extra bucks.
Each edition has a core group that will forever remain faithful to the release of their choice. Like a gold-mining sluice box, customers will slowly roll from one edition to another, but ultimately some of the gold settles right where it wants. I know 2e players that will never move on. To them, 2e is the gold-standard of RPG tabletop gaming. Are they wrong? Hell no. It's a personal preference, and far be it from me to put some stink in their joy. The same goes for 3e and retroclones (BEMCI, OSRIC, and Pathfinder). In fact, there's a reason some of those retroclones have done so well--especially Pathfinder!
In this armchair managing, I don't foresee this as having a burden that is too immense. The company would need to hire freelance developers to look over content, editors to help comb through the submissions, and probably one full-time employee to head it up--to form the DDI team. Articles don't need to come out every day, for every edition. Heck, even once every other week would be enough to snatch up extra DDI subscriptions that would otherwise be ignored.
In the end, I think the benefit of supporting all editions would generate enough profit to support the cast required to produce it. As well, WotC scores a major PR hit by reaching back and tossing bones to the older fans. Who knows, maybe while my 2e buddy is reading an article from his edition, he might sneak a peak at something newer and like it?
I'm not sure all of this would actually work in practice, but I'm willing to listen to what people think is the worse that could happen. I think DDI has potential to be a solidifying glue--one that could be great for fans from all eras. If any company could pull this off, it would be WotC. Despite some of the grognarding on the Interwebs, there are some smart people there.
Matt James is a game designer that lives in the Washington, DC area. His works include Soldiers of Fortune, Monster Vault: Threats to the Nentir Vale, Lair Assault: Attack of the Tyrantclaw, and Into the Unknown: The Dungeon Survival Guide. When not designing content for DUNGEONS & DRAGONS®, Matt is endlessly working on developing new and fun games.