This doesn't sound like a new funding model. Releasing a free open-source product as a "teaser", and then charging for things like: support, customisation, add-ons, security patches for old versions, etc. is already done, and is IMO the best way to make money from open source. Canonical, Red Hat, Elastic Co, and many more already do this.
So I'm not saying the article is wrong at all in its assessment, just that it shouldn't claim to be something new.
I think the "new" aspect here is that the open source software isn't the same thing as the premium version. The core product is similar but the problem it's solving is different and so are some of the features. I can't think of other OSS funding models that sell quite different products to fund the OSS side.
I actually think Aether Pro is a revelation for software engineers and remote teams. The async nature of the app make this way less disruptive to flow than Slack but it's also so much more organized and visible than email threads. I only started using it recently but I'm already excited by how it'll help my team communicate better. The Pro offering is a very similar product to the OSS version but the audience, benefits and use cases are entirely different and effectively it's a brand new product in itself.
So I'm not saying the article is wrong at all in its assessment, just that it shouldn't claim to be something new.