I'm pretty sure they will still be around. I have no connection to them, other than following them on social media for years, but if they were going to do a rug pull that would have happened a LONG time ago. It's a little surprising to me that it's taken this long for them to start taking orders, since their first demonstration flights with a pilot inside were so long ago that I can't remember how long it's been.
It's basically a scaled-up electric quadcopter, but with 8 motors and an unusual shape that's more optimized for forward flight than for hovering. From an FAA standpoint I'm pretty sure it's an ultralight, so it'll probably just be used for joyrides around small airstrips. "Flying car" is the last thing I'd call it.
Anyway my point is that there's nothing that's hard to believe about what they're selling. It's basically just batteries, motors, props, frame/body, seat, controls, canopy, seat, and controls. Anyone familiar with building and flying radio-controlled quadcopters has surely had the same idea, other than the usual shape (which btw is pretty cool, but it looks like landing must be kind of awkward as you basically have to "back it in" every time). It's fundamentally just existing technologies and some product engineering, and the long development process says to me that they're more concerned with getting it right than with spending other peoples' money.