But the context of these phrases is totally different from the one involving Joseph.
In your first example the end of the age is used for emphasis. Like when I tell my wife I will love her for 100 years, that doesn’t mean I’ll stop loving her when I’m 146. But the time period we are talking about with Joseph is 9 months tops. If I told my wife I’ll love you for the next 9 months, I don’t think she would take it as a complement.
In your second example the the activity is continued until it accomplishes an effect. For example if I said I ate until I was full, then that doesn’t mean that I never ate after I was full. But unless Joseph’s steady non-consumation was what caused Mary to give birth, this doesn’t make sense.
As Shodan said. If the authors wanted to indicate that Joseph remained celibate they could have just said “Joseph didn’t consummate the marriage.” There is no reason to add the extraneous phrase “until she gave birth to a son”