No one thinks that. I, at least, have never read anyone who has made such claim. Where did you get the impression that that is a widely-held belief?
Perhaps I should have qualified that statement with "in terms of large american companies", which is what Drucker was talking about.... Companies whose product catalog became bloated over the years in an effort to serve every need of every customer and ended up doing nothing terribly well.
Maybe it's just computer companies? Toyota's website seemed easy enough to use, but then again it was nearly as easy to choose and configure a Ford.