Launching a new startup that sells hardware is more difficult, due to the increased capital requirements, but I don't see any reason to think that it can't be done, IF you can identify a legitimate need and produce a solution for that need, that creates value for the user. Whether or not you need to write in Assembly I don't know, but if working in C floats your boat, just imagine all the "things" you could build that might - for example - embed an Arduino to solve some problem.

OTOH, if you don't necessarily need to get all the way down to the hardware, but just want to solve hard problems that go beyond doing CRUD webapps, there are all sorts of avenues open to you. AI / machine learning stuff, systems level programming for middleware, VOIP stuff, and gosh-knows-what-else. Just keep your eyes and ears open, think outside the box (yeah, yeah, I know, cliche warning), and keep looking for opportunities.