The reason for the tariff war is because he wants more companies to come to United States. So he thinks increasing tariff of each country will help that to happen.
But it is very possible that this will fail. He has paused the tariff for each country for 90 days but he increased China tariff instead.
Tariff wars will never attract more investors to the United States or boost domestic manufacturing. First of all, to be able to produce domestically, it will take a lot of time (many years) to relocate factories, recruit workers...and pour tons of money into it. Second, what if tariffs are agreed upon and eliminated? Cheap goods from other countries continue to flood into the United States, causing domestic manufacturing businesses to lose money or even go bankrupt due to competition.
Trump's term is only 4 years, too short to maintain that plan and investors are aware of this, so they will not invest in the US and manufacture. That's not the real purpose of the tariff war.