I run a small business, know plenty of small business owners and this isn't really the full story.
Small businesses do frequently fail, but it's more to do with the fact that anyone can start one than the fact that they are small. If you allowed random people with no experience to start billion dollar megacorps, they'd fail too.
And there are plenty that generate pretty serious profits, triple or more what you could earn in a traditional job.
It's only a small sliver of the small business space that ends up being economically succesful.