Ask HN: Is there more money in greenfield software projects or maintenance?

It seems that most software contractors target greenfield projects -- e.g. We'll help you build your app idea.

Of course, those projects also tend to use newer technologies.

However, I'm certain, the base of existing code is orders of magnitude larger than new projects in development.

In your experience/opinion, is it more lucrative (hourly rate and volume) to build a consulting business to target a legacy technology like .NET WCF?

Or, do the hourly rates tend to be lower, and opportunities fewer, for projects extending and maintaining legacy technologies?