That's true if you're looking at proprietary systems.
But open source has a ton of "best of breed" projects. In the field of business intelligence alone you have Pentaho, JasperSoft, BIRT, and I'm sure there are others I need to apologize for not mentioning.
It's typical that a New York-based business magazine won't see much below the Fortune 500, but c'mon! Does Hamm really think these companies are completely captive to a single supplier, willingly paying monopoly rents, refusing to consider alternatives?
Consolidation is the natural reaction to the threat of open source. It's proof that open source is making real progress in the business market.
The only way proprietary solutions in the enterprise space can compete with open source is by merging. Open source is like medieval Huns who force the peasants back into a few heavily-fortified castles, then slowly transform themselves into goulash-loving Hungarians.
(Thus the picture, John Cleese as Mr. A.T. Hun, from the famous Monty Python sketch. Now available as a greeting card.)
This is just the way business evolves. The challenge of the new forces those of the old into ever-higher redoubts, but in time those castles are taken as well.
The idea that, in 2007, big business magazines still haven't figured this out is startling to me. Don't they know what Microsoft was just 30 years ago?