Webflow is so far ahead with CMS and now membership that it'll be hard for open source to catch up unless it moves significantly faster.
I think if this product integrates some kind of popular node CMS it might be able to compete. I might be wrong but it just looks like an front end editor similar to GrapeJS
You are correct regarding CMS. Same story with e-commerce and other things.
In fact fundamentally the architecture is built around the idea of not having those things built-in but rather providing APIs for others to create integrations with any data source: CMSs, Databases, E-commerce etc.
Webflow and others with built-in CMS have a massive amount of problems, because there is no one CMS that fits all.
Even harder is e-commerce.
So yeah, we are not going to compete on that because we are not building any of it, but instead focusing on architecture to support integrations.
Webflow CMS is expensive, I can see a small business starting out with Webflow and getting locked in. I can't see a more mature business doing this, as they'd want hosting flexibility. WordPress page builders don't have any hosting lock-in.
I think if this product integrates some kind of popular node CMS it might be able to compete. I might be wrong but it just looks like an front end editor similar to GrapeJS