In fact not a case of either/or.
Data Scientists need to be rounded in the line of business and LOB staff trained to be able to query data, test intuitive thoughts with self-service BI.
A very good article by Craig Saunders at Xerox
Analytics is not a ‘thing’ that can be bolted on. Like any innovation, is has to be truly embedded and supported across the culture to get the full payback everyone is seeking. That is very hard to do if you outsource absolutely all the activity, so in order to balance investment, platform agility and the ‘secret sauce’ that lets you differentiate, there will inevitably be a mix of internal teams and external suppliers/partners, and getting that mix right is crucial.