Really depends on the type of output. For content marketing that most people are just going to skim over anyway (aka is just going to be used for blogspam/content farming, which is what it sounds like the linked writer was doing for this client), yes, it absolutely makes financial sense. But a lot of output is very much winner-take-all: music, movies, TV. Only the top 1%, for some definition of top, of that stuff is actually purchased in meaningful quantities. 60% of top quality of that is worth the same as 0%, which is nothing.
> What if there was a cheeseburger that was 50% as good as McDonalds but was only a nickel? That'd be real bad for the McD's share price.
Not so sure about this; you can look at, for example, generic store-brand colas, which taste exactly the same as Coke and Pepsi and are cheaper, yet Coke and Pepsi haven't collapsed after decades.