Most people greatly underestimate how much it costs to build anything. Even a simple Toothbrush may cost over $1.4m to just bring up a production line to get inventory.
Most startups have a 1:22 chance of making it past 3 years, but if it is a hardware related item that drops to about 1:132 success rate.
Most modern startups just re-sell pad-printed/branded gadgets out of China, or partner with China factories to meet volume demands needed to reach a profit mode.
With the tariff situation, only a sucker would take that bet these days. =3