which may not be common, but
My mother's mother (my only grandparent still living when I was born) lived with us because my mother was a widow and had to be the creadwinner. She was the one in the home when I returned from school. She was kind of a narcissist - I know she wanted me to love her but tried to do it by giving me stuff - not terribly expensive stuff, usuallt y stuff she had made - but tjat was not what I was looking for. She was the kind of person that if you tried to talk to her about something she had done that you'd like her to change would justt deny it. If it was something you could shpw her proof that she had done it, she would just double down. I don't say this is a direct result, but I never wanted to have children, and certainly never dreamed of wanting grandchildren.
My mother was a child of first generation immigrants bothe sides. = she never knew a grandparnet. You know, I hear and read stories about parents telling kids they wan t grandchildren (and usually driving them nuts with the obsession.) My mother never said a word on the subject until I got married at 38 - and then what she said was "Don't make me a grandmother."
I suspect thta not having a positive relationship wth a grandparent can influence people into not wanting offspring. In a Malthusian way that might not be a bad thing, But it still seems sad.