I don't think so.
The article is almost 4 months old.
But here's the real deal.
Southwest has a mature labor force with much higher labor costs than JetBlue.
Ex-fuel, JetBlue has about a 1 cent CASM advantage.
Until you correct that for average stage length.
JetBlue's ultra-low CASM has been achieved with an average stage length of roughly 1300 miles, over twice that of Southwest (617 miles, IIRC).
Once you correct for the average stage length, Southwest enjoys an advantage
DESPITE higher labor costs.
You cannot say enough about the advantage the single fleet type gives Southwest.
Neeleman felt he was smarter than the guys in Dallas, now he owns two foreign aircraft models....the Airbus, which is a decent enough aircraft although I've had a whole lot of A&P mechanics tell me it isn't built to last as long as a Boeing (which probably means minimal residual value at the end of the service life, which probably means JetBlue ought to be depreciating them a little bit steeper than they are, which means their costs are higher than they report)...and the Embraer 190...which some people call the 180 since it taxiies out to the active, does a 180, and returns to the gate.
JetBlue has admitted the Embraer's will be more expensive to operate than their Airbus, which will raise their CASM. Having two feet types complicates everything, and in trying to cut costs, simplicity is everything.
Remember now, I am talking about CASM ex-fuel. When you throw fuel into the equation, the guys from Dallas have a significant advantage.
So while Southwest's fuel hedges dwinde to nothing over the next 3 or 4 years, JetBlue's fleet ages...requiring maintenance that they have heretofore not really had to deal with. Their workforce are going to wonder when they should expect a bigger slice of the pie....sooner or later, most airline employees are going to want to quit being at will employees and are going to look to collective bargaining. JetBlue's labor costs will rise. Pilots on the Embraer are going to want to upgrade to the Airbus and that will require training which is going to cost money....then the First Officer on the Airbus is going to want to step down and be a Captain on the Embraer and that is going to require training yada yada yada.
Bottom line...neither carrier is doomed, but JetBlue has a lot of work to do if they hope to emulate the past, present and future success of Southwest Airlines Co.