Do you not believe though, that consumers and producers will make decisions based on these inputs?
Consumer yesterday has a choice of $1 chinese toy or $1.10 US toy. Chooses Chinese toy.
Tomorrow: If Chinese producer doesn't make any adaptations, they will get $0. US toymaker makes $1.10 no tarrif collected
Our economy is very efficient, that means that even a few percentage change in price/costs of items will have a huge shift.
Chinese producer can either take $0 or lower their price to 90 cents. In that case. Consumer can buy either toy for $1.10, chinese producer makes either $0 or 90 cents, US gov takes either zero or 20 cents.
It's obviously more complicated than that, but I expect, if these hold steady, US production will increase, imports will decrease, prices will rise (but not by 20%), and government income will raise (though not by 20% of today's imports)