I think one issue is that much of the investment and returns in your equation come from overseas production and foreign subsidiaries of US companies.
For example, tires. Goodyear. They have a massive factory in Dalian (in the North, where the better aluminum smelters are). They make tires for the Asian, EU, and US markets. Would tires made by Goodyear - a US company - in China be subject to tariffs when brought back to the US?
If so, then you will reduce the profits and sales of Goodyear China operations.
It’s not a simple “take from here and you will get more there” type of game, because of the nature of business. Tariffs will actually hurt US companies who have wholly owned manufacturing plants overseas, thereby reducing investment AND consumption.
That is true, but the profits for US companies that outsource jobs are going to be coming under increased taxation, and quite likely soon. Congress is looking to close the yawning deficit and taxing companies that “send jobs offshore” is a very popular political target, and the taxes can be implemented without running afoul of any trade agreements.
A tariff is a tax on a product, and runs afoul of the agreements. Taxing profits — not so. Taxing executive compensation? Even easier to pass.
The problem for all of these companies is that very soon, they will have a significantly reduced market for their products in the US because the US consumer won’t have wage growth to buy said products. As it stands now, ALL the job gains of the last 10 years are gone. ALL of them. Actually, more than all - we have just crossed a threshold where we now have fewer jobs in the private sector in the US than we had 10 years ago.
Why is that? Because of what you just said: Goodyear put their new tire plants outside the US and are exporting the result back into the US. Well, that worked as long as the US consumer was able to extract a seemingly never-ending increase in home equity via HELOC’s. That’s now over and done with - for at least a decade, if not more. US Wage growth was stagnant throughout the last 8 to 9 years, except at the highest ranges of income. This is not a sustainable model on which nations outside the US can export to the US. In order to peddle exports to the US, you need a US consumer who has money to spend. Absent more reckless lending, the US consumer has had no increase in organic spending power over the last 10 years... and they’re likely to not have any more spending power in the next five to 10 years at the rate we’re going, either.