It’s not news to anyone that NATO could win a (conventional) war with Russia. The important result is that any sizable chunk of military force in Russia itself stands a good chance of it.
Why risk nuclear armageddon when you can conveniently switch sides at the slightest occasion. It's not like armies marching to shuffle a few chairs in big offices were a matter of deep ideological conflict or worse.
I think you should do some research on the topic before you conclude that "NATO is out of ammunition". I highly recommend Perun https://www.youtube.com/watch?v=deK98IeTjfY .
I'd look to how NATO ran out of PGMs etc when fighting in Libya. I didn't see a big uptick in arms purchases after that. Also, Germany recently crowed about sending 1000 155mm artillery rounds. That's like 3 hours of firing at Ukraine's current rate. The reason Germany has been so slow to provide weaponry to Ukraine is that it is a shell of its former self. The Kriegsmarine has been a joke for decades, the Luftwaffe can barely put 60 aircraft in the air, and the Heer has fewer tanks than Poland, and most of these tanks are in poor condition and shared with the Netherlands.
NATO is not what it was before 1989, and will take decades to come back up to a minimally acceptable level.
There are huge institutional challenges for this to occur. Production facilities have all been consolidated (as they have in the US since the end of the Cold War.) Budgets are also a problem; the majority of NATO members aren't even making the 2% of GDP goal. And there are also some demographic issues; the population of the EU is aging and military service doesn't have as strong an appeal. Will Germany reinstate the draft?
And some things do take decades, even in perfect conditions. Building up a navy takes time due to the long construction timelines for ships. Developing coordination for combined arms operations requires both good officers and non-coms. These take time to develop as well, and need to be continually sustained.
Especially if there's been reports it's seriously been considered in Ukraine.