"The low cost model has only a limited life span before rising oil prices and a raft of proposed taxes and environmental laws, all designed to keep the riff raff out of the sky make the business model obsolete."
I'm glad that somone else has also acknowledged that fact. I've been saying it for ages!
This is why we have Low-cost Carriers...
In the past ten years in the UK and indeed some other parts of the world there have been people, who ordinarily would not be considered 'well-off', in possession of inordinate amounts of expendable cash. Primarily due to the remortgage of over priced properties and inexhaustible amounts of credit. The credit experiment had never really been done before; in that oiks and the financially irresponsible were given 'free munney'.
I recall growing up, where flying was the preserve of the 'well-off'. The 'rich kids' in school would have one, possibly two foreign holidays a year. The late nineties arrived and the 'cheeky' weekend away on the Low-cost carrier appeared as an inherent part of British culture. These low cost airlines are just a feature of the masses having extra expendable cash.
However... The buck stopped! The vast amounts of cash from sold/remortgaged properties has now been spent... but in order to "keep-up-with-the-Jones's" it continued on until well into the late two-thousands... On
credit cards... Until finally every one of those was spent up, too. The Economy ground to a halt, initially referred to as the 'Credit Crunch' and a temporary financial glitch: but everyone with more than two brain cells knew it was a Recession starting. Rest is history...
However... the Low Cost Carriers are still doing okay...
How's that, then?
It's not because the masses are still having long weekends away, but, because the 'high-end' passengers have
temporarily down graded from the Legacy Carriers.
My opinion is that once business returns to the UK and the Legacy Carriers start to pick up their 'business grade' clientele, again, that there may not be a real 'niche market passenger' for the Low Cost Carriers like their was back in two-thousands.
This is when I envisage a return to 'normality' within aviation... or as normal/healthy as it can get. It's all economic...
Essentially... oiks won't be having foreign holidays like they used to. 
P.S. The people who I've described as having more money than sense earlier, are also the ones who probably have bank-rolled 'Little Johnny' through his CTC/OAA and then SSTR.
"A recession is where the wealth in a country shifts from those who don't know what they are doing, to those that do."