Forming the possessive singular of nouns ending in "s"

Factual Questions
1

Strunk and White say that that adding an apostrophe and another “s” is the way to go (e.g. “James’s bicycle”) aside from specific exceptions, such as ancient proper names like “Jesus.”

I’ve found it quite rare for people to actually adhere to this rule, though. I see the supposed error repeated nearly everywhere I look.

Has this rule changed, or do people just ignore it? It’s still present (and, in fact, is the very first rule on the first page) in my copy of the fourth edition (1999) of Elements of Style.

2

Oh, and a related question. Why were the ancient proper names excepted from this rule?

3

AFAIK, the rule still remains. It’s a style rule, though, so it doesn’t have to be followed. Still, most pro writers stick with it.

4

There has been much in this forum on this topic. See the unofficial FAQ, which includes references to previous threads here as well as a sampling of outside authorities, who all have a different notion.