I think the cost of development is forcing these companies to have such a high upfront cost that the majority of high profile games are almost doomed for failure.  Publishers need a hugely successful game to cover the cost of developing their other games.  If game X fails it puts games A, B and C in trouble because the Publisher can no longer afford those games.  So how can a publisher/developer recover?  By selling their high profile properties for a lump sum to keep the company going in hopes of another game becoming successful.  Thus the trend keeps on going. 

I know some people think Nintendo ais crazy with the Wii but it appears that they knew this cycle was happening.  They decided to change the gameplay "experience" instead of the gameplay "technology."  So far that seems to have worked out for them but so many publishers and developers still seem to be playing catch up to Nintendo.