I have to disagree with much of this, though my perspective is more limited, as I haven’t sailed on the other lines.
What makes Cunard special to me, always more than the dress code, is the sense of peace and space and serenity. I’m always baffled where all those 2,000+ passengers are, though the ones I do come across are usually courteous and friendly. I also like the calm decor, which even QA has, the classical music, the excellent libraries, and the varied lecture programme. I would not expect an organisation supplying holidays to lecture me on how to dress any more than how to clean my teeth. I would think most passengers know.
It is nice that people generally dress smartly, and I have never seen men in anything approaching swimwear in the Commodore Club, and can only assume it is a very rare phenomenon. And indeed what were officers, inert or otherwise, doing there? Generally speaking, people who don’t want to dress for formal night go to the buffet, and the best of luck to them. Nonetheless, on my last cruise, on poor QA which seems deemed by many to be halfway to the end of civilisation, on formal nights, my restaurant was very full, and I only saw one person (slightly but not conspicuously) inappropriately dressed.
Why all this gloom?