I just don't buy all this talk about the glory of the 757 and how no machine on earth can, now or ever, do what it does and it is sooooooooo irreplaceable and whatnot. Its a good plane but it is replaceable on most (if not all) routes that it does. Heck most of the routes that it does are also done by numerous other aircraft types. Yeah I guess that 4pm flight can only be done profitably by the 757 despite the fact that all other hourly flights are done by different aircraft types.
I'm sure there are a few "high and hot" places where the 757 is the best choice. But other planes can certainlly serve those markets too. If the 757 at the end of the day is just so awesome and amazing that no plane on earth can do what it does in a few select markets then we will pay to reskin as many as we need, and/or replace the ones that are doing routes that any plane can and does do all day long well before they cycle out, and reserve those for the special routes, and/or the market will build a plane that does what we and others need it to do. One or the other (or all of the above).
Again its a function of economics. The 757 has a cost and a payload in every market. There is a cost to reskin them as well as to replace them early on less mission critical routes to preserve limited cycles for the routes we need. Other planes can do the routes that the 757 does but may not be able to carry as much and that has a cost. All these costs will factor into the equation and we will end up just fine. We're not going to see a massive route extinction across our network just because the pilot group's sentimental favorite plane that looks cool and climbs awesome becomes by its definition too expensive to reskin and the aircraft market doesn't exactly duplicate what it does. Even if the retirement of the 757 means we will have to replace those few routes it radically outperforms other equipment with other equipment, that by no means will result in us abandoning very many markets, if any.
Its a great airplane. Boneyards are filled with great airplanes. But we will be able to replace, or afford to keep, whatever plane is best for the market...757 or something else, and the sun will rise the next day.