To hell with running a successful business. I'm interested in my happiness as an employee, and an open plan office is a thousand times better for that.

Edit since I'm getting downvotes: All the articles I've seen about the pros and cons of open plan offices mostly focus on productivity. But, as an employee, I'm much more interested in my happiness than my productivity, above a reasonable minimum. These sorts of articles tend to ignore that tradeoff.

This article does discuss happiness somewhat, but the results are less clear than those for productivity. I think it's pretty clearly something people disagree on, but this fact tends to get swept under the rug by authors who focus on the productivity losses.