You’re calculations are way too simple.
I am not going to talk numbers but I can tell you that when I was looking to buy my condo, the location/price/timing was perfect but I didn’t have the cashflow (first yr Banker) to put down a decent downpayment, so I had to take a mortgage. I was able to pay off my place in 2 years thanks to the bonuses, but I can tell you that it’s not so easy for many people who have families/significant others.
You are just starting out in your career, so it’s easy to throw out numbers and how much you will save, but when it comes to reality, that’s a different matter. After a few years, I was able to purchase few investment properties using straight cash, but I wouldn’t consider that to be a normal experience for most people. So I wouldn’t condemn those who are looking to buy a house to provide shelter for their loved ones.