have you given any thought to what you have taken for granted now that you may have to discard in, say, 300 years?

This is getting old. You've been hammering at the same point over and over.

I wonder why people like us who talk about wanting to "live forever" don't think more seriously about what that could mean in terms of overturning our current assumptions and background conditions

If you think seriously about what living a lot longer than current norms would have to mean, then you'll realize that everything familiar to you now will eventually vanish, and new things will take their place.

that just means that these women haven't thought very hard about what living a really long time could mean

This relates to the phenomenon of getting on in years and realizing that the books which mattered to you earlier in life don't seem to have aged well when you revisit them.

I don't see how you can "found" a religion and know that it will stick around after your death

I wonder how this political subculture will look in the coming years as its Boomer adherents continue to die off

This is obviously a very important matter for you, but why repeat the same argument, why ask the same question a dozen times?