I will offer you a direct counter-example. When I moved to Warrington I wasn't certain how long I'd be here, and didn't want the hassle and expense of owning a property, plus I would never have been able to buy one due to a lack of capital. Therefore I rented one.
In your ideal world with no landlords I would have been unable to move anywhere except back into my parent's house, and would basically have been unable to start my career due to lack of relevant industry in the area where they lived.
Buying a house is a pain. It takes months, costs lots of money (solicitors, survey etc), has various risks attached, and incurs stamp duty after your first time making it even more expensive. Once you're in the house you either need spare capital (on top of your mortgage deposit) or access to more credit to cover any unexpected expenses (eg have to replace a broken window or boiler or repair the roof etc) and have various responsibilities you don't as a renter. You then spend even more money when you want to move out (which in my case could originally have been after only a year) on estate agents, solicitors etc, with more paperwork and hassle, and the date you manage to move in to your next house can be delayed over and over again.
Renting avoids all of that delay, hassle and cost. It's just completely false and dishonest to claim landlords don't provide a useful service. I settled down a bit and was able to buy a house here several years down the line, but would never have been able, or even wanted to buy a house when I first wanted to move here for work.
Yes it would be nice if prices were lower, but that's a completely different issue to just pretending that buying a house is a realistic or desirable option for everyone.