[fmobus]

If the supplier is forced to leave the business, that is a form of paying. They are losing a source of income and will have to pick a different activity that they are not efficient at. In the case of tariffs on international trade, the supplier loses a chunk of market - in the case of the US, one that was wealthy - and that always means a loss for the business.

The burden of ALL taxes falls on both sides of the transaction. The proportion of the burden varies with market conditions, the most important being elasticity.

That's why studies like the OP are necessary, to determine how much the proportions are. Honestly I am not surprised with the result, tariffs are objectively bad. Curbing trade is bad by default.