The modern CDN web stores content at hundreds of locations, but the locations are all sponsored (paid for) by the original content provider, presumably that pay

The modern CDN web stores content at hundreds of locations, but the locations are all sponsored (paid for) by the original content provider, presumably that payment is subsidized either monetarily by the end-user or by advertisers. So there's really no difference. There are a couple of cryptocurrencies aimed at settling the bill for hosting activity like this that may improve the reliability situation (by creating a monetary incentive to do that hosting)