I agree with the author about the obvious statementst such as many companies have to give their software away for free just to gain market share... I think it has alot more to do with Microsoft's dominance than with the Internet. It is true that open source couldn't exist without the Internet but that is NOT the reason why people open up their code; they do it to compete with proprietary companies... It is a marketing strategy more than anything else...
Furthermore, open source's appeals most in areas that are broadly uses like OS, databases, programming tools (everybody has a computer who needs these tools, hence broad appeal)...
But what about Banking Software (financing sectors), POS, Health Care, Insurance, Manufacturing... etc..... there are software packages in the Real Estate Market being Sold for $2000.... THOSE just don't have that broad User appeal... those i doubt you would ever see open sourced
Open Source at the end will only give ever software developer a good framework, but proprietary software companies will continue to exist and more specialized
We will never see a cryptographic ATM key transfer system for Bank Transactions.... called GNUBank
Open source is nice... but it ain't the whole story.