Ask HN: Are 9 months for building MVP too much?

Hello, I am sole founder / developer / enthusiast, that did leave very well remunerated job spending now 7 months of my time and resources to build lovable product. Occasionally I have verbal checks (less than 5 times so far) with potential customers on where I am at but due to the nature of their work I cannot rely on enough involved on their side. There are no iterations, no pivoting in any form. I rely heavily on my experience, market research and faith if the product is done properly - there will be paying customers. I am not doing this because beliving I have the greatest product fit idea but because of the nature of the product and market that requires the full product flow built up and seems going to require 9 months. I have tried some seeding at couple of places in past few months and did fail. Am I fool continuing?

Keeping in mind that the above is not recommended, I was hoping to see in the comments some related experience showing negative or positive outcome, as well some advices.