I worked in an environment like this before and found it unsustainable. The number of defects and mistakes from everyone in the open-plan area was significant and was a major cause for re-work. Even though the company was making money, it was clear that the noisy workspace was causing them to leave a ton of money on the table, because it was simply not possible for any engineer to create things of minimally acceptable quality in that environment.

There are also concerns for engineers with misophonia (extreme physiological aversion to ambient sounds). For these engineers, though they may be able to do the job exceptionally well, the physical workspace is needlessly prohibitive, bordering on discriminatory, and the idea of using headphones would not address the underlying problem.

I feel this is one of the biggest health issues facing software engineering as a profession (whether it is applied to quantitative trading or banking or making a WordPress site). Hopefully more developers will continue to express their uncompromising need for adequate privacy and quiet in their workspace, and companies will respond by restructuring workspaces to respect these unavoidable human needs.