You can try to save enough money to buy a property without a loan, but will most likely never be able to reach such goal, or you will be too old to actually enjoy it while your family grows. So the choice people have to make today is either rent forever and loose that money for good, or pay back a bank for 20~25 years (with interest) and actually own a valuable asset that you can liquidate in case of major life change.

Note that it is way more expensive to rent forever than actually pay interest on a loan.