Apart from the physical comfort aspect, how does your single class cabin separate the business traveler from crying babies and screaming kids?
Sorry, it's flawed.
As is the thinking that sitting in business class somehow insulates you from babies and kids. I'm often taken aback at the number of youngsters who must be multi millionaires despite not being able to read or write.
I used to think Club World was a good product, then switched to Virgin who don't differentiate between First and Business - their Upper product is superb.
As for PE throughout, I think there is room for both E and PE products. I know a lot of E travellers who upgrade to PE just on the way home; the thinking being that you'll put up with E for 8 hours on the way out because you are going on holiday and the "prize" at the end is worth it, but coming home you want a bit of shut eye and some comfort especially if you are landing in the early hours and going in to work that day.