Just the frequency of certain memes... "interfaces", "design this Design that DESIGN", "composition", "too coupled", "too decoupled", all points me in the direc

Just the frequency of certain memes... "interfaces", "design this Design that DESIGN", "composition", "too coupled", "too decoupled", all points me in the direction of excessive use of DI, indirection, and as you say - explosion of tiny "single purpose" types. I've worked on many such code bases. I don't deny the benefits in testability and extensibility, but I think the benefits have always been outweighed by the difficulty of onboarding new developers, the fact that few people manage to develop a big-picture understanding of how the whole thing fits together, and the proliferation of YAGNI-violating code that ends up being written.