The common denominator with those "other" big companies is not cost of labor but a failure to respond to the market and provide a properly priced, competitive product. There has been a lot of blame placed on the Unions, but it is well to remember that both management and the Unions entered into the agreement. It is also wise to remember that these agreements have long been voided, yet are still blamed for current poor performance. We have never approached peak Legacy pay rates and are still a long way off with the current TA despite tremendous profits.
The Legacy carriers are in a much more competitive market than FEDEX or UPS because the capital costs to enter the package market are very much higher than the passenger market.