Just wait until we stop subsidizing chinese epacket shipments. I bet those illegal drugs coming in with fall off of a cliff assuming china doesn't renegotiate the terms.
I agree with you on that bombs thing. Currently USPS mail is very underscreened. All (or almost all) drugs in the US and coming in use USPS mail due the fact they need a warrant to open your package.
They currently have greatly stepped up their screening game though, mostly due to fentanyl. But that doesn't mean you have to ship straight to the US in bulk. A common route for fake pressed xanax was alprazolam powder to canada where it was pressed and either reshipped or smuggled into the US.
It's not the cost, it's the tracking. China epacket is not tracked, every other form of shipping inbound to the US is. So it will be a lot easier to get caught.
Your argument would work better if the EU wasn't also source for this sort of thing. Though the availability on that end has gone down due to a Russian lab being busted earlier this year that turned out to be behind two of the bigger source sites.
Spend a few hundred (even after losing a few shipments) and you can still easily make it back with one good shipment getting through.
Honestly, I think that the bombs getting sent to government officials is going to hurt things for them more than shipping costs would.
we'll see what the future holds though.