While I dont deny that J class in Europe is abit of a con much of what youpay for isn't really on the plane
its the change the ticket at last minute, shorter check in deadline no queues to board use of thje lounge and pretty much an assured blind eye to carry on bag size.
if you are running around Europe every week all this becomes very important because its tiring and those frequent flyer points that mean you take the significant other to Bermuda occasionally helps keeps you from ending up single. Also seeing as you have often got up very early -missed lunch and travelled back to the airport at evening meal time even an airline hot meal is very welcome as youare not going to be at your front door or hotel room until 9pm which is bit late for eating. So yes it is a bit of a con, especially the on board difference but if its your way of life then it makes a big difference.
The amusing thing is that marketeers bang on and on and on about branding and positioning but when it comes to flying people only look at the price most of the time