Southwest and US Airways are two completely different things- the light rail and the steam locomotive.
If US Airways parked every aircraft but the 737, stopped hubbing, discontinued service to all international points and all of the smaller cities (so the whole network really), and only flew point to point between the top few cities, then you can compare.
If you want 80 people an aircraft, you cant have widebodies. If you want 20 minute turns, you cant have first class. If you want lower costs, you cant have Clubs, interline agreements, alliances, or such a complex and comprehensive FF program.
US Airways is A NETWORK carrier, with a redundant network, at least two fleet types for every mission, short haul routes, a million non-interchangeable express carriers, poor product due to understaffing, a beaten down and unappreciated workforce, overpaid management, and an overcomplicated, ridiculous pricing system.
Those are what makes US Airways not a low cost carrier. Fundamentally, network carriers are different than LCCs, and US still is one and plans to be- whether or not they use buzzwords like "hybrid" or not. They can be a smarter one like America West, but they will never have the inherent low costs of a Southwest or JetBlue no matter the labor contracts are, if they stick to thier current model. You simply cannot compare the two.
Could they radically transform it into a real, full blown LCC? Yeah, but who needs another one? Whats needed is a good network on the east coast, a good Carribbean/LatAm/Europe network connecting smaller cities to the larger Star Alliance, and offering a slighly premium product. Does the whole airline need to be more efficient? Absololutely! From the top down! I want to hear about streamlining and resloving the basic operational and fleet stupidities of the airline, and where the whole thing is going. I want to hear about a fair pricing structure that doesnt punish or alienate the customers. I want to hear about a reasonable product, provided by US Airways employees on US Airways equiptment. The contracts can be made more efficient along with the airline, but you wont convince me that Wal-Mart wages are OK for anyone.
As for the original question, well, if you started an airline, it would likely be an LCC and thats how you would operate. But we're talking about a 75 year old network carrier and a management that wants to look like and cost the same as American but have its employees think of themselves as low-cost. The airline already has built in costs associated with its basic product- network carrier, and then add on all of the US Airways stupidity on top of it, and you've got a terrible set-up even if everyone worked for free.
If they are going to compare, at least America West comes close to what US Airways looks like. None of the others are like US at all. We dont hear Southwest much now because they pay much better than thier US counterparts now.
Since they are so obsessed with these "not like us" airlines, it amazes me that they dont take the number one reason for success from them- TREAT YOUR PEOPLE WELL. That is a huge part of WN's success. Most network carriers treat thier employees as liabilities, and blame them for problems. At US Airways, they had one of the most experienced and passionate workforces in the industry, that a parade of different "leaders" came in and blamed, threatened, lied to, and smeared thier reputations PUBLICALLY. They have demoralized thier people so much that people are ready for the plug to be pulled on thier once-beloved airline.
Thats what will bring down US Airways, not that they dont turn an A330 around in twenty minutes with three people.