If one wants children, is planning on children, one wants good public schools for them, and those are generally found in areas with significant population and higher land values. If you can plan around home schooling and one parent staying home to conduct it, rural living may be a great choice. But trips to libraries might be long, and fast internet connections unavailable or unaffordable. Those amenities are available where population is denser.
It is, in my observation, a popular HN myth that amenities only exist in hyper-dense and expensive cities. But it's not true.
In my very suburban (low density suburban, surrounded on two sides by forest) area the library is a 10 minute walk away at toddler-speed so my child has been an avid visitor as soon as started reading a tiny bit. Schools are also walking distance (high school will be a bit farther, but within easy cycling distance, about 2 miles). And yes, we have internet in the suburbs.
This might not be what you want to do, or hear; I know it wasn't what I wanted in my late 20s. But you could own a house within a year or so if you decide you want a house more than living in an expensive area.
I spent my 20s banging my head against an impossibly expensive area trying to find something and perpetually failing (in my case, NYC). In my late 20s I gave up, moved to a very suburban (borderline rural) area and bought a house right away.