Or maybe there's no problem at all and the Bloomberg reporter doesn't know what he's talking about?

Some quick Googling suggests that Toyota outsources up to 70% of their parts. (http://artoflean.com/index.php/2014/01/07/444/)

VW is much more vertically integrated. (http://www.autoblog.com/2012/12/06/how-volkswagen-is-run-lik...)

  "How can this be possible? How can VW look so uncompetitive
  from a productivity standpoint, yet out-earn all of its
  competitors?

  "Ah, that's the magic of VW's corporate structure."