What can we learn from the nidche?

If Judaism doesn't believe in collective punishment, why do we fast and do teshuva for the sins of our fathers?

Why did G-d wait until the daughters of Tzelofchad complained about not having an inheritance before writing new inheritance laws into the Torah for them?

Why did G-d create the multitude of galaxies? Doesn’t this render the Earth as nothing but a puff of a speck in the universe without much importance?

Do these findings prove that the universe is billions of years old?