Whether or not we agree with Dark's approach doesn't invalidate it in any way. It may mean we don't understand it. There are plenty of companies selling non-FOSS tools and making others successful with them. FOSS does not mean a secure future by any means. The fact that they know they have to prioritize making it a sustainable business is a good sign.
Using any tool, and depending on it commercially, is a risk. You weigh that against who is behind it, the path forward if it goes away, etc. It's easier if you can keep building even when the company goes away. If you rely on their servers, there is always more risk. Is there more risk to a project like Dark than FB's Parse? Nobody can say, without inside information.
What you have to look at, when selecting any tool (ignore the fact that there's a language component here, or that we're devs), is the benefit and the risk. If you have a stack that works for you, and you don't think there's a problem with how you're doing things, don't change. It's really that simple. But there is a revival of RAD, called Low Code, that says there are a lot of businesses out there with needs that aren't being properly met with our "modern" dev processes. If you can get a working product out, and it runs for a couple years, that's a win if you couldn't do it any other way. If you only use Dark to prove a concept, rewrite it after that if you're scared it will go away. Once you have a working product, though, good luck convincing the business it should be rewritten without strong justification.
But we can step back even further and ask: Do you think the state of software development is great? Just OK? Don't see any issues? Do you think that complexity is killing us and things we call solutions really aren't? Or are you somewhere in between?
In watching the videos, there are some things that aren't to my taste. But they note that this is not the final product. If you watch Paul's video, can you deny there is some deep thinking behind it, smart people who have already done a lot while being forced to make real-world compromises.
Yes, it's a business, but they're doing it to make our lives easier too. Shouldn't we cheer them on and wish them the best of luck?
That's what I'm doing.