Automation World magazine has an article, Walled Garden or Open Field? by John Berra. He opens:

There is thoughtful debate over the best approach to automation in a fully digital world. Some argue for moving the walls out to include everything; others argue for the complete demolition of all walls.

John notes the divergent paths of Apple, Microsoft, and Google:

Apple does not license its operating system and exerts very tight control over its hardware and software. Bill Gates believed in the opposite approach and licensed Microsoft software to multiple hardware manufacturers. Google is doing this today for its Android operating system.

He concludes:

So, my view is that control systems and field devices should be walled gardens with open communication between them. I recognize that there are other opinions and invite you to share them with me and each other. By the way, I moved my photos to an Apple.

Automation World has a LinkedIn group discussion thread where you can weigh in, or add your thoughts below.