What the article missed is that there's a growing market for the middle-ground in terms of Economy Plus/Premium Economy products. I forget which airline (CX? BA?) recently said that their PE cabin was their most profitable overall.

Not everyone is going to settle for park benches in the back, nor find value in paying for a super-premium product up front, and that middle-ground option is becoming more widely available on airlines the world over.

With domestic U.S. fares in First coming down dramatically of late, I think the next big change will be that First will be renamed Business on most domestic routes, with First reserved solely for 3-class aircraft flying on transcon routes. It would be a fairer representation of the product offered.