Biblical names stick around by virtue of being Biblical names. They are notable, a lot of people will have seen them, and they are (were) extremely culturally relevant. You'll also find that different Biblical names tend to be kept by speakers of different languages depending on what's easiest to pronounce.

People are still named after non Biblical figures like Alexander and Helen for the same reasons, even though the two originators of those names were born ~2400 and ~3200 years ago, respectively.