Looking at it from the other side of the mirror, there's probably some other suite of factors that causes both things. Taken as a prisoner's dilemma, defecting from R&D may be perceived to have a payoff ( those engineers talk funny and cost a lot ) which saps R&D and also slows growth.

I think that in an increasingly specialized workforce, the management team has less bandwidth to apply to R&D. One stump hit and it's done for. Successfully leading R&D has little payback in the larger economy; leading M&A is better understood. This is a corollary of the general "tower of Babel" problem.

Remember that Amazon is slightly a tribe of madmen to most business types in large companies.