Continuity mistake: At 38:20, T'Pol (as acting captain) says that they have resumed their course to Azati Prime; however, from 39-42 minutes, Captain Archer and Trip discuss the "current" status - that they are still orbiting the planet and then the Captain orders Trip to tell Travis to set a course for Azati Prime at maximum warp. (00:38:20)
Continuity mistake: The captain's log date of Jan. 8, 2154, doesn't align with the timeline of previous episodes. Harbinger, two episodes earlier, was said to take place Dec. 27. The episode in between that and Hatchery, Doctor's Orders, wasn't given an on screen date, but T'Pol compared the anomaly in that episode to the one in Harbinger, which she said was encountered a few weeks earlier. Even if that was just two weeks earlier, that would put Doctor's Orders at Jan. 10, and that episode spanned at least four days, so the earliest Hatchery could take place would be Jan. 15.
Answer: While ratings did drop, there was a lot going on to cause the rating drops and cancellation. First, "Enterprise" was on UPN, which was dissolved a year after the show was cancelled. At the time of cancellation, it was UPN's highest rated drama. Because they were on at night, they were often preempted by local UPN broadcast of baseball games. And it wasn't even aired in every market. They also lost a major corporate backer early and it was difficult for them to over come that loss. Plus, for season 4, they switched to a Friday night line up, so they were competing against Fox shows, like "The Simpsons" whereas on Wednesdays they didn't have much competition.
Bishop73