No one else trying the same thing as your startup is a far bigger problem than being second. If no one else is doing it then you have to single-handedly prove there is a market, spend the money to educate people that they have a problem worth spending money on, and do all the work to figure out what the problem is and how to solve it in a way that represents value to your customers. That's really hard.
Leaving those problems to someone else and being second with much cheaper solution that can undercut the company that was first is often a pretty good strategy.
3 years in R&D sounds very normal for hardware projects. That scares me a lot to start something really complicated alone. I persuaded myself, that it’s just hobby and crawling slowly forwards.
3 years for software is enough to 3 times succeed of fail.
I already sold 3 companies doing the agile thing, I'm quite aware of the known problem/unknown solution approach. This time I'm more interested in the unknown problem/unknown solution space and, for this particular project, that meant inventing a new branch of mathematics to solve a particularly hairy problem.
In short, a non-static, continuous, non-deterministic neural network that can span infinite state by estimating an NP-hard convex optimization problem.
Leaving those problems to someone else and being second with much cheaper solution that can undercut the company that was first is often a pretty good strategy.