Which makes large active fleets extremely difficult to maintain, and makes energy storage or fuel efficiency a major research area.

It would be costly to keep a large or even medium number of ships active, while more primitive technology makes it more realistic. No more power cores that can keep a ship running for years without end. Better to be more realistic, rather than just poop out ships as fast as possible, and not having to worry about ammunition, fuel, crew, or anything. It's just production of ships, and there ya go.

Now what about the basic labeling system? The ship can be anything, but just put it in a category.