To counter your hypothetical "can't be done", here's a real example of a product company that's grown a single person selling electronics kits from their college dorm room to a product company making $33 million in revenue less than 10 years later:
https://en.wikipedia.org/wiki/Adafruit_Industries#History
A similar example being this product company, which started out in 2012 with two people and a laser cutter, growing to a product company that employs 30+ people within the space of 5 years: