Not at all, after Crimea, some things were "tested" and the outcome was more or less as described.
As long as Russia is only gathering troops
How do you know they are "only gathering troops" - will you wait till first shots are fired ? Somehow western Germans wouldn't have been too happy if the US, UK and others adopted that approach during the cold war.
there is nothing even "Fort Trump" can and would do
There's a damn lot of that. It places on the Russian side responsibility for potentially triggering off the WW3 and they are not really dreaming about it. Any Russian leader thinking seriously about something, which might bring open confrontation with US, will get poisoned (or "accidented") by their own people: generals, oligarchs etc.
Do you really believe that Russia will attack and invade Poland?
Not much but there are other "scenerios".
1. They might collaps the financial markets here just massing the troops along the borders and making some "hawkish" speeches. If you add to that half assed reaction of NATO... would you be willing to buy Polish bonds then ?
2. Quick, limited "Georgia style" intervention. Why ? "Victory over NATO" - that would be Crimea X 100 on the "domestic market". - that's the reason why I personally believe that unless NATO becomes at least 10% of it was during the cold war, we should just leave this mess. It's better to declare neutrality than to be in ineffecive alliance, 39 comes to mind.
I can't imagine any full scale NATO-Russia (or rather US-Russia) conflict but I won't be surprised If one day I wake up and hear that Russians took Estonia over night. That's the thing, with NATO turned into some metrosexual discussion club, you can achieve that without starting the real full scale conflict.
Of course, they could elect to stay in the barracks and stay out of it.
Just like US dudes in South Korea could "elect" to stay out if it If Kim invades... From now on, I am ignoring your "input" here, it's a waste of time.