So if they said "You should only be profitable if you make constant improvements." Then that is what they meant. They didn't say "You should only be profitable if you make constant improvements or if your product is good or if you serve a genuine need or if...etc."
In fact, the OP said "The constant need for improvements is why we use capitalism at all." Which leads me to believe that they meant exactly what they said. It happens to be false, but totally conforms with their absolutism about profitability.
I obviously don't agree. There are many companies that make good products and are profitable and I believe should remain profitable without the need to change the products they make. You seem to agree. That is good, because "You should only be profitable if you make constant improvements" is a ridiculous statement.
That's my point. I don't know what's bold about it or why anyone would agree with it generally and I think logically it's easy to counter.
It's about this statement: "You should only be profitable if you make constant improvements." - do you think that restaurant deserves to be profitable?