I think it comes down to is the project there to make money or not. If it's mainly for money then it would never start out open source (ie AWS) but if it's a solution to a problem that can be improved via collaboration then it'll be Open Source (ie OpenStack). This hasn't really changed over the years.

What we are seeing here, as others have pointed out, is that companies are buying Open Source solutions and then close sourcing them because they view it as a money maker which in the end leads to forks.