There are two aspects of software which make it unique in the world of Economics.

Immortality and essentially Free Duplication.

Immortality usually leads to higher prices - eg gold diamonds etc

100% Accurate free reproduction means no supply limits and which leads to zero cost.

If software does what is required and will continue to do that from now until eternity - what is the point in re-design.

Its not as if accounting theory has changed much in the last 500 years.

When open source reaches the required level of stability and usability I think the market will naturally migrate.