Tableau provides easy to use, best in class, visual analytic capabilities, but it does not help with plumbing (data foundation). We could, for example, marry SQL Server with Tableau to get the complete package. Tableau licenses are relatively expensive if we are looking to scale.
Traditional BI can handle it all but with significant upfront costs, higher consulting, hardware, and software costs. Among the mega-vendors, only Microsoft can provide a reasonable value proposition. Open-source vendors like Pentaho and Jaspersoft do not have an abundant-enough talent pool, yet.