If it's just "hello world" in this day and age of good frameworks, great open source tooling like Terraform and SaaS offerings that's not too tall of an order.
It looks like they are leveraging Netlify for their website, Gumroad for payments, and Notion for wiki. This helps to make as much of what is not actually the product (marketing, documentation, financials) as easy and fast as possible. Most of that hour would be actually making the product (the web extension).
Given a talent for design, and some marketing, and some experience making extensions. This should be possible within a reasonable time frame.
Through practice and experience you can reduce the amount of time it takes to make routine actions and decisions. But the bottleneck is making good decisions about matters that are not routine, and every new project has plenty of those.