sorry I don't understand the whole home ownership thing

we rent a brand new house pay 1/2 the amount it would cost of we had a mortgage(rented it from the bank) and invest the difference. We still have an investment and have a great house as well we don't struggle with mortgage repayments. When the rented house gets a little tired we move into a new one again. When we want a holiday we take one just cut back on the amount we invest that month.

Buying a house why you never OWN it anyway the bank does, and as far as rent money being dead money what is interest?