"I really don't see why they couldn't have been doing this all along."

They could have.

Trump was definitely right about Europe. They've let the US cover the cost of the defense of the continent. Now they are massing forces to a posture in which they can collectively defend themselves.

I know Trump and Hegseth sound nasty, but this is that come-to-Jesus moment that Europe needed. If there is a war in Europe, China is very likely to exploit the sitch to take Taiwan. The Pacific is the US's military priority. That means that US forces would shift their focus there.

Europe is sort of an easy fight. There isn't really an outcome where Russia achieves anything that the rest of Europe doesn't concede to. The Pacific is a different story. You would have fighters flying from some location like Hawaii or Alaska, getting drug behind a tanker to the front line, doing their vul, and then being drug back to Alaska or Hawaii. I've done it in bombers and it's a tough ride. In a single seat fighter, you will quickly ruin people. China isn't the biggest adversary in this fight, it's the tyranny of distance.

"They're doing this because they correctly see the United States as being the enemy, along with Russia."

I don't think it's that at all. I spend as much time working with our foreign partners as I do US people. What I do think is that they are coming to terms with is the fact that the US will not take the leading role in a fight in Europe, because the focus of the US will always be the Pacific. And that's nothing new. The "pivot to the Pacific" began under Obama. It's just that no one wanted to acknowledge that.