Maybe they think: come to us, we have a product that is best for you, no matter which one you buy just spend your money with us.
Look at their architectural offerings: AutoCAD LT, AutoCAD, ADT, Revit. If I look at Autodesk, I usually have the impression that they do not necessarily kill new programs, instead they integrate them in their portfolio and position them in different ways. I looked at both Green Building Studio and Ecotect about 2 1/2 years ago and they looked pretty different programs to me, Green Building Studio being a simple web-based service with a few functions to give you some sort of idea of the energy consumption of your design, while Ecotect is a much more sophisticated program, basically a complete building design and environmental analysis tool for all kinds of analyses, including solar, thermal, shadow, acoustical, ventilation/air flow, building regulations check etc. But you're right in that it's highly unlikely that they'll let 2 competing products continue side-by-side. Bingo!!!!! They will likely cannibalize it for features to integrate into Green Buidlng Studio (if they can) and then euthanize it ala Lightscape by ceasing all further development and support for it in future versions. They wouldn't develop two competing programs simultaneously I would also assume there will be some kind of consolidation of the features to some extent.
