But the reality is that companies are getting pwned over and over and nothing bad happens to them. Actually looking at cost-benefit it still makes sense to get to market quickly.
Of course, as we all know, it never happens. BigCorp continues to churn out buggy, leaky, unoptimized code, and customers keep giving them money for it. I suppose you can handle this in a number of ways: 1. You can accept this and re-adjust what you consider to be "good enough to ship", 2. You can get jaded and dismiss all software customers as morons, or 3. You can start your own company that TAKES SERIOUSLY the proper use of namespaces, and see if that lets you outcompete the competition.
What is the argument? If you start thinking about it, I think you'll find it's actually quite hard to create a coherent counter-argument.