I don't think the renting example is that true. AFAIK auto manufacturers certainly do "rent" many of the factory machinery they use, and they certainly "rent" the maintenance contracts from the companies who service them (the big exception I'm aware of being Toyota, which makes their own factory robotics).

In other examples, many airlines do lease airplanes, and even among the airlines that do own the planes, they still usually lease the engines.

As the GP said, there's a balance to be struck. Delta doesn't have the expertise or the economies of scale necessary to build their own engines from scratch, but they do have the ability to lease those engines and then have their own teams maintain them. Similarly, most companies don't have the know-how or the EoS to run their own data center, so instead they buy cloud services and then have a smaller team to maintain it. It's a win-win. Some companies like BofA might be big enough where they can run their own cloud and it be cheaper than using a cloud provider, but that's definitely not a common thing.