Well, again, Purity Lake's view is the grasshopper's, not the ant's.
Yes, renting is cheaper, and we could get by day to day. But someday I'll be old. Jobs will be harder to come by, and I may not be well. Having a place of my own then will be important, as will the equity in the house.
If you're 25 now and thinking "oh, well, I'll focus on getting a house when my kids are grown," keep in mind you may be well into your 40s by the time that happens. I can tell you that age discrimination in jobs starts before 40 for women, and that breaking in to a good salaried position is much harder at 45 than it is at 30, particularly if your education is out of date or incomplete. Is it possible, for many, yes. But for some it's a long stony road. Also, when you get that magic salary, you'll find when you go to the bank that you'll be paying a mortgage until you're 75.
These numbers are all very abstract when you're young. One of my college roommates is 43 now; her mother needs care, and increasingly one of her sisters needs care. She hasn't got any children, thank God, or she'd be going out of her mind. She's paid rent in NY all her life, and has more or less nothing saved, even though she's got a job that pays in the 70s. Last year, when her landlord of ten years suddenly kicked her out, she tried to scrape together a down payment for an apartment and couldn't do it.
I realized for the first time that she may be in real trouble when she's older. Rents in NY will not go down. And even if she managed to buy a place, she'd still be paying a mortgage in her early 70s, though probably retired and living on -- what? Social Security? Maybe, if it's still around. Pension? Doesn't have one. Savings? She's got all of $20K saved so far. Parental help? No, there's only her mother, and while her mother owns an apartment, it will almost certainly go to pay nursing home costs. So how is my friend going to pay a mortgage at 70? Who will employ her that long? And if she can't pay a mortgage, how on earth will she be able to afford rent, which will be many times a mortgage payment by then? I don't know where she'll live.
So no, houses, places of our own, these are not luxuries. They're not necessities today. But we'll be alive, God willing, for much longer than today.