I expect you've come across the following:
Heisenberg argument for his uncertainty principle took into account the act of measurement in 1927. Specifically, measurement causes a disturbance that it quantifies in terms of the energy carried by the measurement itself - and then one takes a limit. Leo Szilard's solution to Maxwell's demon also revolved around measurement. The demon needs to measure the speed of molecules and the act of acquiring this information requires energy.
Prior to this, of course, was Poincare's & Einstein's theorizing that the measurement of time had to be rethought in 1905.
These examples, hopefully, give at least some heuristic indication as to why measurement became a closely studied topic.
Realism, broadly construed, takes the objective existence of the world out there as a given. Newtonian Physics took this picture for granted - the clockwork universe - the objective character of time & space. In this picture one does not need to measure the world out there to know that it is real and has an objective character - and is independent of observers. This is of course a metaphysical supposition.
Presumably it was the impact of the discoveries outlined above that made the scientific community rethink this supposition, and to tighten up what it is that was known properly. They turned to epistemology where one considers how one can be sure that the knowledge one has is in fact valid.
It was the Vienna and Berlin school of logical positivism that developed out of this that became the main steam of Anglo-American philosophy - today referred to as Analytic philosophy - though one sees here that it had continental roots. This philosophy, because it considered only measurement to be valid, and thus true, dismissed that which could not be measured as being ontologically not there at all. They argued, if there are no possible conditions under which a particular phenomena can be measured, then what right have we have to say that it exists. For example, Since one cannot see isolated quarks, they would argue that quarks are not ontologically real. Whereas, a realist physicist, would say they're obviously real - they're always confined.
Hence, despite the emphasis on measurement, logical positivism is seen as an anti-realist school.