"People who rent homes" aren't some special type of consumer that isn't interested in buying a home. While there are situations where renting is preferable even if it's possible to buy, many renters only rent because it's not possible for them to buy a home. Any potential benefits to renting are generally outweighed by the fact that you're not building any equity, and have limited control over the place they live.
Massive corporate landlords aren't providing a service to meet a demand. They're actively creating demand by driving up the cost of home ownership, and limiting the amount of properties available to buy. A potential homeowner has no chance of competing with a massive corporation when buying a home.
Obviously there's a huge amount of factors that got us here. Housing is hugely complicated, and no single group is responsible. But corporate landlords are one of the factors making the North American housing market worse, and are one of the things we need to address if we're ever going to decrease the cost of living in this country.