But he's been saying crazy stuff for a decade now, and didn't implement stuff like this before so I can see how people were surprised.
This is easy to reason through if you just remember that Trump and his cronies are not smart or competent. They have basically no concept of how to follow through on a promise if there’s any complexity to it.
Take a look at the list of kept promises from the first term: https://www.politifact.com/truth-o-meter/promises/list/?prom...
And the list of broken promises: https://www.politifact.com/truth-o-meter/promises/list/?prom...
The kept promises are trivial, while the broken promises include everything that can’t be accomplished by executive diktat. (Such as lower prices, unless he directly puts a price limit on goods in an executive order.)
Basically the only value in reading into his non-trivial promises is in considering “how could he make things worse if he follows through on attempting this?”
But yes, you can clearly see from the market that you have been much smarter, if your company was confident enough to take action to spend a lot of money to hedge against this. You'll make out like bandits if the tariffs remain, so congratulations. Truly, anyone who saw this coming and shorted stocks appropriately is now rich. That's how unexpected this was.
But Trump was promising vengeance on cultural issues and immigration. Not on prices. Again -- voters expected him to follow through on his promise to lower prices. Not to raise them massively.