ENT did not fail because of continuity but because of risk aversion on the side of the fans and the studio. Trekkers were pissed off that the show dared to deviate from familiar patterns like a piece of classical music during the intro, the studio didn't greenlight Berman's suggestion to set the first season partly on Earth and while B&B did good innovative work the show felt too often like an echo of VOY during its first two years. And in its last year, as good as it was, it felt too much like an echo of TOS.
So yeah, you could claim that ENT failed because nobody wanted to actually do or see something new.
About the Ferengi, there exists nothing but a log entry in the files about one among hundreds of alien races the Enterprise crew met just once. This very file might have very well not survived the Romulan War plus two centuries and if it has it exists in limbo somewhere in Starfleet's databases. It is certainly not something anybody would have actually read, probably not even Data.
So yeah, you could claim that ENT failed because nobody wanted to actually do or see something new.
About the Ferengi, there exists nothing but a log entry in the files about one among hundreds of alien races the Enterprise crew met just once. This very file might have very well not survived the Romulan War plus two centuries and if it has it exists in limbo somewhere in Starfleet's databases. It is certainly not something anybody would have actually read, probably not even Data.