I think it also depends on your upbringing. I’m one of 3 (I also have a sibling from a parents second marriage) I love my sisters - but my experience growing up in poverty influenced my decision to only have 2. With a 6 year age gap to ensure we could afford it.
My parents both had jobs - but not ones they enjoyed or progressed in. To go on holiday once a year my Dad would took on second jobs and during the summer would have students staying in our bedrooms.
It’s more than just being able to afford it. My middle sister was bloody hard work growing up and it affected both me and my younger sister. I think if my parents had a crystal ball they may have not had a 3rd with how challenging the middle one is! It affected the parenting for the rest of us!
I would have loved my own space and room growing up - I’ve read here having your own room doesn’t matter - it really does. Having space to study away from the crazy would have helped.
I also would have liked more children but knew I wanted them to have their own rooms, and choices. We only go on holiday every other year so it’s not about holidays! Now my eldest has just finished uni we’ve been able to support her and make sure she has the opportunities we never had growing up. Driving lessons and helping her buy a car - insurance. Also, it’s expensive for her to move out so she coming back home to her bedroom to start her grad job.