I imagine if Google weren't effectively subsidizing ChromeOS machines (by not charging for ChromeOS, and instead hoping you'll spend more time on their web properties and ads), most of these machines would cost a bit more.

All the things you mentioned cost money. There are psychological barriers (marketing speak: price points) where people make different decisions.

For example, $500 is a magic point where something stops being either affordable/inexpensive/casual expense (depending on your financial situation) and becomes unaffordable/expensive/notable.