Exactly, Brabazon.
It has astounded me for many years why BMI, BA, etc haven't exploded the "low cost" myth put about by Strokios, O'Lordy, Beardy & co.
Certainly, with the "low cost" carriers, if you make your booking when the seats are first released, you can pick up some amazing bargains. But, if you book close or very close to your travel dates, you will find yourself subject to some serious "price gouging".
In almost every circumstance, I have found (my preferred carrier) BMI to offer the cheapest fares on the routes I travel (most of which are also covered by the "Low cost"s). And now, with the move by BMI (and BA) to a "low cost" sales model, it is much easier to compare prices.
In fact, I "switched" (apologies to Apple) to BMI from Easyjet about 4 years ago, not only because the fares on British Midland (as then was) were lower, but because on the primary route I travelled (LON NCE) there wasn't even any availability on EZY in the summer season. Moreover, by using the BM EuroPass I was even able to travel biz class with guaranteed seat availability at a lower price than I could get on EZY cattle (sorry economy) class!
Of course, once I moved to BMI, with its friendly cabin service, I just couldn't face the prospect of the "every man for himself" boarding scrum, and the "we are sorry to announce that we haven't got any hot water to make tea" amateurism of EZY.
The sad truth is that "low cost" (which is a biz model / corporate costs issue) is not (necessarily) synonymous with "low price", and the consumer needs to made ware of this.
One way to overcome this "deception" would be to obligate ALL airlines to show price range (for the comparable seating class) in their adverts rather than headline "from" fares. This would be much fairer (no pun intended) to the travelling public.
Just to be clear, I am not averse to travel on "low cost" carriers, and have travelled on the excellent GO on many occasions; alas even this avenue will disappear once EZY import their "value proposition".
Finally, many of the UK "low cost" operators doff their caps to Herb Keleher as the man from whom they take inspiration. But, if you have ever travelled on SouthWest, you will know that the UK operators offer a very poor quality product by comparison!
My $0.02