I think I understand where he's at. If your web site has compatibility issues with smaller browsers like Firefox at 3%, Opera at 2% etc. then you could be losing out on 5% of your sales. If you were to approach any CEO and ask if they'd be interested in an initiative to increase sales by 5%, they would most likely express an interest.

there is good chance whoever site didn't worked for will just switch to chrome for that site. I did that few times.

We have "any browser above 5% market share" in deals with our clients. So FF testing is not even required

I mean, I don't object in principle, I in general consider this to be "doing a good job" that we all strive for, but in this particular case it was a "line of business" app with like 500 users so I genuinely hadn't even considered it. We'll see if it comes up later!