It’s because all of those things were already (somewhat well-known) idiomatic phrases in English.

Even a quick google search shows me plenty of examples for each. “The good doctor” is sometimes used ironically, sometimes not, and has been for many years; “the good wife” had different origins but seems in the mid-20th century to have come to refer to the sort of model American wife; “good cop” is more common as it is used in the phrase “good cop/bad cop” so it isn’t quite as big of a stretch; “good place” is the similar to “good cop” because it’s used in juxtaposition with “the bad place,” which is mostly used as a way to avoid saying “hell” for people who think that’s a swear word, and it’s just extrapolated from that; “the good witch” has probably been around for a while but was popularized by The Wizard of Oz and Glinda, the Good Witch. This probably doesn’t cover all the shows named like this, and I definitely think there’s some synchronicity to the whole thing, but it isn’t necessarily just lazy writing/naming.

TL;DR: these examples in particular are just existing English phrases (or parts of common phrases).