mike-wsm
747 1500lb/seat
VC-10 2200lb/seat
Brabazon 2900lb/seat
Concorde 4000lb/seat
Which would you buy?
747-100 1,626lb/seat: commercial success
Concorde 3,433lb/seat: commercial failure
Britannia 310 (close to your heart, surely?) 1,330lb/seat: commercial failure
707-320B 2,269lb/seat: commercial success
VC-10 2,220lb/seat: commercial failure
727-200 1,108lb/seat: commercial success
HS Trident 3B 861lb/seat: commercial failure
Douglas DC3 792lb - 1,013lb/seat depending on config: commercial success
Vickers Viscount 810 900lb/seat: commercial success.
All MTOW/PAX figures from Wikipedia.
It looks to me as if there's a bit more to it than simple MTOW/passengers. How is it that the Viscount supplanted the DC3? Why aren't we all still flying around in Daks, or Trident 3s? Oh, because of the A380, which in 853 pax 1-class config manages 667lb/seat.
Edit 17/12/2010: the quote is from mike-wsm, not Jig Peter, to whom I first wrongly attributed it.