I think you missed my point. This statement is something I can't really get behind: "If another single company can turn off your app it is centralized.". Storage isn't the only point of failure/way to turn off an app. I listed several above.
Let's say you created your own storage facility to not be controlled by another company. The government can turn off access to electricity or internet in that facility. If the app is mobile only, Apple and Google can stop the distribution.
To be truly decentralized, are you saying that a small company will create their own global datacenters? That they need to create a mobile OS that can rival Apple and Android in adoption? Not only will that cost a lot of money, I don't think their earnings can pay for all of that.