The prices of things are not what they are worth, but what the market will bear.
The 30 year mortgage allows a rich man to outbid you on the home that you want to buy to live in, a property that he has no personal interest in, so that you can pay interest on the money you only had to borrow so that it could not be loaned to someone else, such that they could afford to pay more than you. That money pumped into the market only serves to raise prices. Houses are built larger and more expensively than they otherwise would be because the buyers are able to pay more.
If there were no mortgage loans available, the market would be producing a greater number of cheaper homes for sale, and a greater number of rental homes for investors, with more economic separation between those markets. The rich man outbidding you for property would have to actually assume ownership of it, and would shoulder some risk of carrying vacant rental units. Venturing into property-owner-land as a rentals investor would evoke a nasty NIMBY response.
Believe me when I say that it is possible for every person in America to own their own home, even with just a single minimum wage job for the whole household. But it isn't bloody likely, thanks to mortgage lending, zoning laws, and building and occupancy codes that completely eliminate entire classes of low-cost housing as either unprofitable for developers or outright illegal.
This same phenomenon is now occurring in higher education, wherein loans inflate the price, the product remains essentially the same, and the buyer is saddled with an enormous burden of debt. Debt is a trap laid by the wily for the foolish. But it persists because the practice nestles snugly into a Nash equilibrium. The practice is not at an absolute maximum, but neither player alone can improve his position by making a different move.
The only way for the erstwhile borrower to win is to form a cartel able to punish anyone who takes a loan to pay for a good or service too scarce to supply everyone in the cartel. In other words, non-rich folks win by regulating the hell out of lending, to reduce the number and amount of loans available.