We don't live in a vacuum. Like it or not, trade and military alliances are still important. Now, is it necessary that other countries like Trump in order to trade or ally with the U.S.? No, not exactly. Trusting his judgment and wanting to cooperate with the guy, though....if they don't, it could make things harder for him.
Our trading partners and military allies have been massively benefiting because America has been the world's *****.
Of course they will not like having their gravy train stopped.
We can't afford to take the hit for the rest of the world anymore.
There's some of that going on, for sure. Not so sure "the hit" we've taken is their fault, though. If you're talking about the slow economy, we priced our workforce out of the market and it took off for cheaper pastures, and automation, to compete in a growing global marketplace. One thing has led to another. If Trump can turn that tide, fine, but from what I've heard that isn't likely without the Delorean from Back to The Future.
The money we have given in diplomatic aid to other countries will be given to them by another "kindly Uncle" and that will be either Russia or China. I'd rather they look to us, frankly.