I own a consultancy and I might find this interesting as I don't have an internal SaaS framework yet.
The two problems I see are:
1. Lack of options... There may be some parts of the stack that I don't like or don't fit requirements
2. Unknown code quality... Cannot tell what the coding standards are. This is related to #1 in that I don't know how hard the code will be to modify unless I read it.
Otherwise it's an interesting proposition. React/Nextjs are my jam, and I prefer serverful (Django) to serverless but that might be negotiable. But even if I wanted to drop in my own server, if the front-end is well coded I could easily save 2x-3x the 1.8k sticker price in dev costs on a single project.
If I were to build a SaaS myself, I might also find this interesting with all the caveats above, but I would 200% certain not pay a revenue share unless the platform really required minimal tweaking and was about 90% adjusted to my use case, and provided continued platform value after that launch (like, say, Shopify).