I largely agree with what you're saying, but at some point some of the workers eating the dogfood become the managers buying the dogfood. Sometimes (hell, maybe the majority of the time) their decisions are self-serving and uninformed; but sometimes their decisions really are based on making the organization as successful as possible under their current circumstances.

It's at this point that we look at what the majority of dogfood buyers are buying and realize that the influence of software developers is probably less than the influence of the people buying the software (sorry for restating the obvious there).

Anyway, the point, if I have one, is that the mass of office workers probably does tell you something about the direction of the software world -- and in fact, if we consider the net worth of IBM, Oracle, SAP, CSK, MSFT, Intuit, Autdesk, etc.; we might find we are at odds about where the 'tremendous' influence is coming from, if there is any such thing as 'tremendous' influence at all.