I think that is because data science is a recent term that has been coined to mean an increase of interest in the quantitative analysis of "data" across a diver

I think that is because data science is a recent term that has been coined to mean an increase of interest in the quantitative analysis of "data" across a diverse number of domains. To abstract what is common across all these fields is not a minor task... But achieving such an authoritative methodology book that will not be a cut-and-paste compilation of different strands is in some sense also an acid test whether the term has long term meaning or was simply a hype term during a particular speculative bubble period.