Those are not the same things at all. In neither of the cases you listed was the US trying to reach them with a small force before the Russians did. (Although they probably should have.) The problem for the Russians in the Ukraine is that they have to move large forces, in this case in order to occupy eastern Ukraine against a potential fight with Ukrainians, whereas a small group of US or British special forces on the NATO side is sufficient to achieve the American objective of blocking roads and transit for Russian forces. If the Russians have to shoot at NATO in any way, they lose, so there is no need for a comparable sized force to match the Russians.

US speed and stealth has been very effective and has had, and continues to get even now, almost continuous, real battle condition experience in Afghanistan, Iraq, Yemen, Somalia, etc. It is very unlikely that the Russians would be able to win such a race in the Ukraine, even starting from a much closer distance.