Onwards to hypothetical land: How much do men care about having descendants that they will never see?
That depends a lot of the particular men. There are man who do care about it but I think the majority doesn't. Sperm banks pay donors instead of the donor paying for the sperm bank accepting it's sperm.
There's an idea I've seen a number of times that 80% of women have had descendants, but only 40% of men. A little research tracked it back to this, but the speech doesn't have a cite and I haven't found a source.
The reproduction rates for men and women (possibly for the whole history of the species) seems like the sort of thing which could be found out, but I'd like more solid information.