Yes, it's true.
There's lots of construction going on in Teton Village with even more to come. It's important to mention, however, that the lots you are talking about are private property. Those lots been open, park-like space for so long that everybody seems to have assumed that they really are just park space.
Instead, "progress" has finally caught up with Teton Village and most of those remaining properties are either under development or soon will be. If it makes you feel any better, Teton County has a building height restriction of 65 feet, so none of the new buildings will be more than about 5 stories.
Here's an aerial photo of Teton Village:
Lot 3295 is the Mangy Moose.
Lot 3269 is common open space and will remain that way.
Lot 3315 is the Hostel.
Lot 3265 is the aerial tram dock and Nick Wilson's Cafe.
Lot(s) 3385 is the CURRENT Teton Mountain Lodge.
Lot 3335 is the one that is presently under construction for an extension of the Teton Mountain Lodge.
Lot 3325 has been sold and construction will start next spring on another condo/hotel/commercial building.
Lot 3395 is the Pepi Stiegler Sports building.
Lot(s) 3405 is potentially under contract and will probably become another condo/hotel/commerical building within the next three years.
Lot 3275 is the current "Village Center" building (home of TGR, Wildernest Sports, and the Village Cafe). This building will be knocked down in the next two years and become a retail/office/residential building.
Lot(s) 3285 is the building Teton Village Sports is located in. It has residential condos on the three floors above TVS.
So as I said, there's a great deal going on in Teton Village.
I do suspect that the views from the deck of the Mangy Moose will be significantly affected by the two new hotel/condo buildings going up in between it and the Teton Mountain Lodge. That's too bad, I suppose, but it's hard for me to get too worked up about it because I'm not a big fan of the Moose anyway. Some green space WILL remain in front of the Moose once this is all completed, however.