Do you have any reasons in mind why would Jobs want to groom Zuck to be his successor? They don't seem particularly similar to me.

I would rather have the Jon Ive / Tim Cook combination.

I like this train of thought. Who better to know who can replace Steve Jobs than Steve himself? (Maybe he just sees a lot of himself in Zuckerberg.)

If such a thing were to become reality, this honestly would be a credible explanation for it.