In the past, has National Code ever approved an electrical service to pass directly from the transformer to an electrical breaker box with out protection of a disconnect, fuses or breaker? Or would that have always been a bad idea?

Honestly, I don't get exactly what you are asking.

If there are less than six breaker throws then no main disconnect or breaker is required.

KISS put an interesting post about the history of the NEC in this post
https://www.askmehelpdesk.com/electr...ng-398059.html

He gave a link to
History of Residential Wiring Systems

In that link it looks like the New York Board Fire Underwriters in 1881, established a requirement for a disconnect at the building entrance.

If you are referring to the utility transformer, no protection is required at the secondary of the transformer serving a service panel. The panel will need a main breaker to protect the service.