This week LEGO announced a massive $237 million pre-tax loss, its biggest ever, and a continuation of its string of losses since 1998. Company president Kristiansen is quoted as saying "Now we go back to the core products, the Lego bricks," and he's sacked five out of his 14 top managers. As the Mindstorms sets have had stagnant (even negative) sales over the last 18-24 months, the speculation is that LEGO will discontinue the product line.
Too, LEGO faces increased competition from other toy makers who are moving into the "stackable brick" market. LEGO lost its important court case against the parent cpompany of MEGA BLOKS, and now several toy makers, notably Hasbro, have come out with "LEGO compatible" toy sets, at prices 50% or more off a comparable LEGO set.
It'll be interesting to see if LEGO does indeed hold on to Mindstorms, and if it does, if they can manage new development to keep it fresh. Their Spybotics line was a failure, and the core Mindstorms set hasn't changed much since its introduction more than five years ago. A small private company that loses this much money year after year can't afford a lot of R&D for new products, especially products containing electronics (the liability risks alone are huge).
It might also be interesting to see if LEGO sells the Mindstorms line. Knowing what I know of the LEGO company mindset, this seems unlikely, but you never know.
-- Gordon Author: Constructing Robot Bases, Robot Builder's Sourcebook, Robot Builder's Bonanza