I am sorry, but this article smells of FUD (Fear Uncertainty Doubt), targeted both at Subversion and at Open Source in general. Why is using an external code repository hosting company like CallabNet any more risky using an internal one, where "the risk of a service provider failing is new and frightening"? Can you provide an example of this, or at least flesh out your argument?
External hosting companies, like any other service provider, are bound by their service level agreements (SLAs) with their users. Furthermore most quality repository hosters should offer daily offsite back-ups of your code and extensive redundancy features. If they don't then shop elsewhere.
As for using Subversion internally, my company does this and we are very happy with it, both technical and from a support point of view, where the Subversion community and online documentation are second to none. We are actively moving all of our repositories from a commercial source control package to Subversion, which we believe is vastly superior.
I would like to conclude by saying that I really do not understand the main point that you are trying to make with this article, as your argument is weak. Are you trying to imply that relying on open source products is inherently more risky than relying on commercial ones? If so, FUD.