I think if you can prove that you can scale revenue or users by the factor of 1,000 within 2-3 years, while only increasing headcount/staff by the factor of 10

I think if you can prove that you can scale revenue or users by the factor of 1,000 within 2-3 years, while only increasing headcount/staff by the factor of 10 then they would be interested. That's basically the definition of a startup, so na matter what you do, if you can prove scalability like this, you are a startup.