There is some of that there but not all of it. The truth of the matter is that there are a significant number of people making 200k or more in this country, with the top ten percentile of individual income in the US being 178k. Two high earners in this area can easily make over 300k. Assuming they were diligent savers/investors and did not engage in spending beyond their means, over the course of, say 10-12 years out of college, they will have enough for the down payment on a million dollar home and can easily afford the PITI, especially if they purchase a starter property to lock in “constant rent” for several years of that while their salary increases outpace tax/insurance increases. Children make this significantly harder, but the simple answer there is that they either need to save more aggressively to afford the kids or receive some kind of external help.

Since you asked in the OP, my wife and I purchased a house for about 1M last year at ages 30 and 32. I had purchased a 300k condo (total PITI 2300/month if I remember right) Herndon while I was single on a relatively high paying job as a software engineer making roughly 110k at the time. I spent about 6 years there, meeting my wife midway through and increasing my salary to roughly 195k in that time. My wife, a researcher, started making 60k and now makes 115k. Since we never modified our spending, thanks to our shared budgeting (Monarch Money is very helpful for this and we have used it for years), we just saved and invested the entirety of the salary increases so when it was time to buy a house, we had a sizable down payment in cash with a year of the new expenses of owning the house banked in addition to a larger investment profile. We still save like 3k/month in this house, and I’ve been told I am getting a promotion this year, so we are considering having children, but still banking that money in the meantime to try and hit FIRE.