Originally Posted by
ajnaro
I agree with sdsearch's analysis. But still, it's hard to understand why airlines would systematically discourage the loyalty of their most profitable customers and cultivate the loyalty of the less profitable economy class customers.
Airlines would go broke if they flew with full J cabins and empty Y ones. It is instructive to realize that SQ, a lauded airline, couldn't make all-J work on SIN-EWR/LAX, and the number of airlines that DO make all-J work is tiny, mostly restricted to LON-NYC.