[Volcano]

A concept which draws an analogy between the span of a human life and that of a product.

Is "that of product", "span of product"?

A concept which draws an analogy between the span of a human life and span of a product.

[susan53]

Yes. "that" is used to avoid repeating what has already been said. Here it replaces (and means) "span". Notice the sentence doesn't really make sense though. It's not the span of a product, but the span of the product's life. The sentence would be better as :

A concept which draws an analogy between the life-span of a human and that of a product.
Now "that" substitutes for "life-span" which is what the writer really wanted to say.

[Volcano]

Thanks