1. Lawyers incur more liability with their work.

2. The quantity of workload they provide per job is less, thus pricing is more dense (i.e. companies realize programmers work thousands of hours for a project and that the project viability would collapse at $700/hr)

3. In many cases you have no choice but to hire a lawyer, while more often you can say no to a programmer should the economics not support the project.

4. A lawyer has to go to school for approx. 6 to 8 years (at least in Canada) while programmers have a wide variety of education levels.

I'm sure I could list more...