Decentralized platforms aren't a business. The decentralized model scales remarkably well for a very small cost because there are hundreds (or thousands!) of instances that run at a small scale and communicate with the broader network. Many volunteers run small instances that cost only a few dollars a month to maintain and are often supported by donations from the users of that instance. You can even run your own instance if you want. Even if one instance fails the network as a whole doesn't even feel it. The financial model is totally different and very sustainable, much more so than the proprietary model even.