Is the Silicon Valley representative of software development though ?
Because on the other hand we have professors telling us that the average (surviving?) software lifetime is 20 years...
A lot of 6 month old code gets thrown away either because its been rewritten or because it didn't achieve its stated objective. Meanwhile a bunch of companies are relying on systems that were first created in the 90s because that software achieves its objectives and the cost justification for a rewrite isn't there.