You don't buy the house evenly across thirty years. You rent the money first and buy the house last — and the schedule shows you exactly when the switch happens.
Take a $400,000 loan, 30-year fixed at 6.5%. The principal-and-interest payment is about $2,528 a month. Of the very first payment, $2,167 is interest and $361 goes to the loan. You paid $2,528 and your balance moved by less than a tenth of one percent.
— Educational, not financial advice.