Substack was considered to be "the next big thing" in journalism and self-publishing a couple of years back, but it's true that it did not live up to the hype or its potential since then.

Still, it's the most frictionless way of starting a newsletter, even though there are services that give users more options and/or more freedom for less money.

But discoverability remains a big problem. If it does not solve that, it will end up being interesting only to people interested in what the "big names" have to say. Those will not remain loyal to Substack unless they are handsomely paid, so this is not a business model that's sustainable. Substack will have to find ways to get more eyeballs on new writers, otherwise it's not going to last. Simple as that.