Non-LTS versions stop receiving security updates as soon as they reach their end of life.
Well, so do LTS versions. They just have a longer end of life.
Running updates on non-LTS versions often fails due to unavailable or unsupported repositories.
This is not true, unless you’re using unsupported repositories in the first place, which also happens with LTS.
The other claims made are generally accurate, but I’d be careful about trusting this article wholesale. It’s more nuanced than that. Ubuntu fully supports its own interim releases. Some add-ons such as ESM and livepatch aren’t available for non-LTS though.