I think it's more subtle than that; it's edge vs core. Edge systems are the ones (non-tech) people interact with, and have a very high turnover. 3270 one day, then Visual Basic, then Cold Fusion, then Java, then AJAX, then... There's a lot of churn so there's work, but there's also a lot of elasticity, a company won't really hurt if it delays projects like this for a year, it can even skip a generation. Core systems are the ones that operate the business. There's a lot less churn here and fewer people employed... But if a change needs to be made to support a new product or process or regulation or to integrate an acquired company, then it has to be done. Similarly these systems have to be up 24/7 and there are people needed to do that.
My experience over 15 years (almost all of it core) is that edge people can make fortunes and get written up in magazines in the good times as everyone jumps onto the latest bandwagon but suffer in the bad times when everyone realizes that what they've got does the job perfectly well and if it ain't broke, don't fix it. Core people have much stabler careers, but will never be "rockstars" (and we aren't interested in being either).
My experience over 15 years (almost all of it core) is that edge people can make fortunes and get written up in magazines in the good times as everyone jumps onto the latest bandwagon but suffer in the bad times when everyone realizes that what they've got does the job perfectly well and if it ain't broke, don't fix it. Core people have much stabler careers, but will never be "rockstars" (and we aren't interested in being either).