Lets presume this thing retails at - very unrealistic low price - of $500.

How many people would buy this weird thing per month - even at this low price point? 10? 50? 100?

Imagine you're an engineer and your competency is worth $200,000/year. If this retailed at 1/10th - as you suggested - so $500, and lets generously say you make $100usd per unit at this price point.

You have to atleast sell ~166 of these "weird" niche things per month, every month, no exceptions to match. And you're probably not a single person, so way more.

Can you? And why bother?

More importantly, can you even make these things for $400usd when your order quantity is only 166units per month?

And this is after spending years(?) in development, and some non negligible amount of cap ex.