If you have a monopolistic ISP that refuses to provide service to you because they don't like your content, and they're your only option, then that's a problem.

If you have multiple tens of CDN providers and they all don't want to carry your content, then perhaps you should really take a look at your content and have a hard think about why it isn't wanted.

And regardless, a CDN isn't necessary to host a website. A CDN certainly makes it easier to achieve lower-latency global reach, and is useful in helping you weather certain types of attacks on your infrastructure, but they're by no means required. And there are other ways to achieve those goals.