I think control and making money are not bad reasons to keep something closed source. I would like to see products going open source when the product is discontinued or, something I have been thinking about, when you made enough money for past and future to fullfil goals. For Wolfram that seems a point reached years ago, but then again, Wolfram his goals are not clear for the future, so you don't know when that part is satisfied. So I see his point and think it's valid.

Like others have said here, if I were Wolfram, I would make it free for personal use and then price it depending on the company size and revenue (like some game engines do). I mean 345 euros for Home Edition is really too much imho; I understand the power and reach of the product, but wouldn't it be better to get more people dependent on it so they try to push it at their jobs/companies?