Amphibious invasions are difficult and the Russians don't have a lot of experience doing them. Also, invasions always favor the defenders. Remember that only about 7,800 Germans total were committed to the fight at Omaha Beach alone, while the Allies committed over 43,000 troops to that sector. The Germans suffered 1,200 casualties while the Allies suffered about 2,400. Yes, the Allies won, but it came at a significant cost and it might have failed had NCOs on the beach not rallied.
While true, this is Nazi Germany we are talking about. These guys were a small country that bloodied the nose of Russia, swiftly occupied half of the Continent and beat us to computation and jet propelled aircraft in the midst of doing so. Imagine replaying that game of Age of Empires knowing not to research Gargantuan Tanks and putting all your marks into Messerschmidt. We'd have been fucked, we wouldn't have jet fighters until the 1950s, and without us no one would have had the homework to copy - or, our copy of the copy of the Berlin Patent Office, at least.
They were innovating at a staggering rate. A side project of Der Fuhrer ended up being the most popular vehicle of the 21st century, the Volkswagen Beetle. VW AG is still one of the top 5 players, and for a minute was the biggest automotive concern in the world.
The USA had to throw massive amounts of money and war materiel at fighting the wrong enemy - Russia wouldn't have even had electricity without General Electric going there and doing the dumbest fucking thing ever, 'hurr durr line go up, let's give vodkaniggers lightbulbs because profit.' In order to fight a war you need more than just pylons pumping out Zergs, you need money and raw material - if not finished goods, vehicles and weaponry for sale. See also the UK, the UK wasn't going to do shit to Germany without massive amounts of raw material and cubic yards of cold hard cash. Those frogs were whittling planes out of wood, ffs. And they did at least make stuff that was the equal of other modern powers, hard to argue with old Bentleys.
Contrast with Greenland. Name one fucking thing Greenland gave the world. Nothing. Even Latin America gave the world some decent music and big booty latinas. Greenland isn't shit, has never been shit - and without American ownership, will never be shit. Iceland gave us Bjork, what's Greenland's excuse? I'm not joking, we could literally just use women to invade Greenland just for the lulz. Guys on standby in case they fumble the ball that hard, but if we wanted to we could have the population fertilizing the tundra in no time at all while playing with them like a cat with a soon to be devoured mouse.
Remember, lol, their military is NATO. "Of course I've seen him, he's me." I think we're collectively in the process of stopping hitting ourselves, ja?
BTW, never blackpill about acquiring territory just because libtards and shitskins live there - statehood is a privilege, not a right. They can just be a territory like Puerto Rico has been - and votes to remain as, thankfully. Looking at you, Canuckistan.
Imagine the Cold War if we were going 'what are we even going to do with Alaska, anyway?' back when. Sometimes as a man you just acquire something to put in the shed or junk drawer, becuase Murphy's Law, if you don't, you'll need it later.