Oh. I didn't know that. I thought there was to be no more single player versions. I saw a bunch of people complaining about how the company was selling out the 'lore' and turning into WoW and how it would be strictly PC since console companies won't sign on to moorpgs. That's a relief if true.
Ever read the story of Chicken Little?
Anyways, the MMO is being produced by Zenimax Online Studios. It also, as I said, takes place some 2000 years before the single player games. I believe it takes place in the 2nd Era while Skyrim takes place in the 4th Era. So, the MMO should in no way impede Bethesda Game Studios from moving forward with the single player series. If anything, they'll be able to draw upon the lore written for the MMO to enhance and further enrich the single player games.
It wouldn't surprise me if the next TES was a next-gen Xbox exclusive.
I'd say that is about as likely as the MMO killing the single player series.