One advantage of more smaller files is that merge conflicts become less common. I would guess that at least half of the trivial merge conflicts I see are two unrelated commits which both add some header or other definition at the top of the file, but because both are inserted at line 17, git looks at it and says, “I give up.”

This in itself might not be enough to justify this, but the fewer files will lead to more challenges in a collaborative environment (I’d also note that more small files will speed up incremental compilations since unchanged code is less likely to get recompiled which is one reason why when I do JVM dev, I never really think about compilation time—my IDE can recompile everything quickly in the background without my noticing).