So they (Axis powers) weren't winning until we stepped in?
First off, dipshit, that's a loaded question. We're talking about the Nazi's, not the Axis powers as a whole.
Germany was already finished as an effective army
LONG before we ever got a fucking foot on the European continent. By June the 6th, 1944, the Russian's had already decimated the German army. The entire third army (some half a million of Germany's best troops and most of it's heavy armor) surrendered at Stalingrad in February of 1943.
After that, the German's were on the run the
ENTIRE TIME. In fact, only once more would they even dare put on an offensive, and when they did they kicked our ass clear to fucking Mars. Had they not run out of gas, we'd have been pushed back into the fucking ocean.
We landed in Northern France on June 6th, 1944 and in Sicily almost exactly one year earlier. By the time we even got involved it was already over in Europe. It was only a matter of time before Russia took it all.
In fact, that's the only reason we even bothered going: to make sure Russia didn't take it all.
Now as far as Japan goes, yeah. We did a lot of the heavy lifting there, but nowhere near all of it. You're the typical moron that thinks sitting on your ass while everybody else works the field busting their butts and then you come in and help pick that last row of tomatoes somehow equates to you picking that entire harvest all by yourself.
You're flat out fucking wrong. We didn't kill anywhere
NEAR the amount of Germans the Russians did. We really, other than carpet bombing the fuck out of innocent civilians, didn't accomplish jack shit in the European theater other than keeping England and other allies supplied with gas, oil and food and military equipment.