What happened in Ukraine and what happens in the Baltics now is like comparing apples and oranges. In other words, it's a speculation not based on evidence (i.e. Russian actual policies towards the Baltics), but on analogy with Ukraine, a country with completely different political climate, culture, and power dynamics than these of the Baltic states. Besides, unlike Ukraine, the Baltics are already members of NATO. So, they don't need units of Western troops deployed to their territory (and dangerously close to Russia, to boot) to ensure their security. Just NATO membership is enough, because no actor, however powerful, wants to fight a powerful alliance of states. And if it's the Baltics, what for, anyway? What is at stake for Russia in the Baltics to risk all invading them? Just think this through.