At some point, open-offices will be the only thing that the majority of software developers know. If you've never experienced the productivity that comes from being able to think without interruption, you won't know what you are missing. At that point, the trend will probably be irreversible.

For me personally, this trend isn't all bad:

When I work someplace with this setup it's kind of nice to "hang out with my friends" even if it isn't nearly as productive.

When I'm working for myself, being able to think deeply gives me a competitive advantage over places with open-offices. :-)