I don't think this is a difference between "Western" linguistics and Japanese linguistics. Collecting examples with relatively little explanation is traditional

I don't think this is a difference between "Western" linguistics and Japanese linguistics. Collecting examples with relatively little explanation is traditional linguistics as it was practiced academically in Europe and Japan and probably most other places as well. You had etymology, and grammar, and many many examples for each. However, modern/computational linguistics has started asking new questions that were simply not considered in traditional linguistics: why and how do the rules of grammar arise? How are they learned by infants? Why do human beings use language at all? How are human languages different from animal communication? For many such questions, looking at hundreds of regional variations of certain words or grammar rules is not particularly helpful, unfortunately, though there is some work that was done based on that as well.