There is vigorous disagreement in the field regarding just about everything. The title of the underlying article may more appropriately be, “Popular Economics for Non-Academics.”
to the average citizen of the world they are indistinguishable
Macroeconomics and econometrics are two major subfields which literally didn't exist in Marx's day: economists may disagree significantly on conclusions and somewhat less significantly on certain assumptions models make, but they're focusing on the same variables (interest rates matter and fiscal policy somewhat matters, inflation is a thing which can be reduced, boosting employment and staving of recessions is more difficult) and doing similar maths.