I have a special appreciation for civil engineering - I just find the bridges, highways, dams, and sky-scrapers beautiful in a way that an engineer can appreciate.
In America, before all the infrastructure was built, one might say that there was a "golden age" of civil engineering. With literally millions of square miles of country, there were seemingly endless opportunities to build new structures. And at the time that these structures needing building (before computers, flight, or bio-engineering), civil engineering was arguably one of the advanced fields of its day. You put these circumstances together: lots of new projects that require advanced technology - and you've got an engineer's dream.
Of course, over two hundred years, enough roads and bridges and buildings were built to fulfill much of the country's need. There were a couple spurts in between - building the highways, the major airports, an occasional monument, and more recently the cell phone transmission towers. However, in general, the civil engineering mindset went from "new creation" to "infrastructure maintenance".
At least from my perspective, the same life-cycle appears to be happening with software engineering. Even back in the 80's, just finding a machine, learning the syntax and writing a "program" was a new thrill. However, especially with the internet (just google the syntax and copy code-snippets), better hardware (you don't need an algorithm-genius to make an application perform), mass availability of machines, outsourcing (huge pool of developers), standard platforms and components that encourage reusability instead of re-inventing the wheel, and simply enough years passing - almost every established company has some sort of core IT infrastructure in place. Back in the late 90's, major companies had huge booms to implement their ERP, email, and websites (made lots of consultants very rich) - but now those expensive systems are in place. Sure, there's always work to do, like integrating components, migrating code, consolidating applications, extending functionality of existing apps, and maintaining existing code. There's still new development, but it seems much scarcer than 10 years ago. The cowboy days of just being thrilled to write a program seem to have passed.
Similar to how civil engineering has filled the country's physical infrastructure, software engineering has filled much of the country's IT infrastructure - and therefore in both cases much of the work currently being done is maintenance. America doesn't make many Hoover Dams or Golden Gate Bridges anymore - but there's always annual road re-surfacing. Same concept for developers. (This means that there's tons of legacy code out there, which is why every developer should read the phenomenal book Working Effectively with Legacy Code.)
Some developers view this in a pessimistic light, as if "the good old days" have passed us by. However, I'm an optimist, and there's much reason to believe that there are still many innovative and new software development efforts ahead.
- There are continually newer technologies - This provides a business incentive to rebuild older systems. Web systems replaced many fat clients. But now web 2.0 is replacing many existing web systems, and mobile apps may replace those, and there will be something after that (what if voice recognition takes off and makes most UI obsolete?).
- Much room for innovation - The nature of IT (with the low barrier to entry, the ability to cheaply experiment, and building projects out of "thought" stuff) allows for massive innovation, unlike any other field I can think of. Innovation means hopes for a better, more profitable system, and therefore business sponsors to fund new development.
- Software applications have a short lifespan. - Most software projects are replaced within 5-10 years, so there is continually new work. (A good bridge or building could last for a hundred).
- Programming is a foundational skill that can assist you with everything else - Because almost every desk job in any industry uses MS Office apps (or the equivalent of), databases, and web sites, the ability to write even simple programs can assist with those jobs. For example, writing an Excel macro or finding results in a SQL query may let you get a task done much quicker.
So while on one-hand there's definitely more maintenance work for all the legacy systems, as the field of software engineering matures, I think there's still a lot to be optimistic about for new development opportunities.