It's not about manufacturing, it's about shipping to end customers. Anything involving the USPS will have almost nothing to do with business-related shipping (b2b). Businesses don't ship stuff to each other with small packets, they ship large quantities in bulk. If you're worried about hurting existing businesses in the US, then stop worrying: US-based businesses aren't dependent on cheap postage from China on Aliexpress. Companies ordering parts from China are getting them shipped in shipping containers, or by DHL/Fedex, not by the USPS in < 1-lb packages.