Just because Trump said 90 days doesn't mean he's actually going to wait 90 days. What Trump says has zero impact on what Trump does. Trump signed the previous trade agreement with Canada and Mexico last time he was in office that he violated with these tariffs.
He just said "90 days" to maximize the market bounce. In two days he'll complain that other countries are not removing their retaliatory tariffs (because real governments value consistency and won't yo-yo their population like that) and I give him two weeks before he puts them back again. A month tops, but that's giving Trump way too much credit.
They very much have. China has just become a convenient "out group" for Trump to demonize.