The thing is that D&D to remain relevant as a brand needs constant retailer presence. Perhaps, the minimum of what it needs to achieve that is a monthly magazine in paper format like what Dungeon and Dragon used to be.
I don't know that the game needs constant brick and mortar retail presence, at least in the form we've grown used to. Think about WoW. You've got the starter disk boxes and prepaid reload cards, that's about it (not counting themed swag that doesnt really affect the game, but keeps the brand publicized, D&D could use more of that too, but its another issue).
So if Erik Mona's correct, and I think its a strong possibility, given WotC's actions and stated intent of bringing the game to a virtual tabletop over the last decade, all they really need to have in stores is a product like the Red Box Essentials to get you started. Prepaid booster cards for your DDI membership would work too. There's also the strong possibility of more random card packs, like the player cards they're doing now. Random monsters, spells, items, etc. The model works well for them with M:tG, no reason to think they won't finally confirm the fears some of us had in 1999 and "magicize" D&D.
Let's also not overlook the introduction of products like the Castle Ravenloft boardgame. If the core D&D game is going online, these kind of products would be good gateways for the tabletop gamers, especially if, like the Dungeon! and Fantasy Forest games TSR put out in the late 70s and early 80s, the games contain a set of "dummies" rules for using the product without knowledge of D&D 4e. Dungeon! and FF both had a feeling of being "just D&D enough" to get players interested in the genre, and the related RPGs, but were easily playable by family game night type players with no wargame or rpg experience.
Later accessories for D&D, like the Dragon's Den adventure set for Cyclopedia era Basic D&D (early 90s) also included similar "dummies" rules, that let you introduce new players to the ideas in D&D without forcing them to learn the rules and role up a PC.
As the complexity of the game increases (again, not trolling for a basic D&D vs 4e flamewar, but there is no arguing that 4e is more complex), the need for intro products like these is even greater now than it was in 1980 when we all grabbed up a copy of Dungeon! And if you can bring in the new players with a product that will also appeal to the established customer, even better. Meaning, those who have played 4e since day 1, and aren't rabid collectors like me, aren't all that likely to keep buying D&D Essentials Red Box type products (unless the products remain high value with limited edition minis and dice and durable dungeon tiles etc), but almost all players will at least consider a boardgame/uberadventure like Castle Ravenloft (especially if it also, as it appears to, includes a bunch of high value swag)
We don't need to get into comparing the actual gameplay of 4e with WoW, it's flamewar bait, but noone can deny that WotC has been envious of WoW's huge success and wants to emulate some of it. It's also foolish to think that, as Erik pointed out, a paperless or lesspaper publishing model isn't something to strive for, from the publisher's point of view.
Aside from the speculated revamping of the business model and new approaches to marketing D&D, the other real possibility presented in the changes at WotC is that Hasbro is finally cracking down and D&D's days are numbered.