Honestly the biggest issue with this strategy is US capitalism isn't kind to companies that just stay small. You're not going to find a lot of places that want to remain tiny, just a lot that, as mentioned above, remain so through micromanagement.

Maybe you get lucky and find a labor-of-love kinda place where someone is just trying to be really good at making one type of thing (highly niche products) but a better bet is to just find a comfy place, stay there a few years and help them get bigger, then leave and repeat.