The reason it might happen is because the US sees China as the main adversary. Europe doesn't hold the same strategic significance as it did during the cold war. With USSR no longer around, Russia does not pose an ideological threat to the US, and now that Russia inflicted a military defeat on NATO, there's no possibility of further expansion east. The US will force Europe to increase their military budgets to 5% and take up the slack https://www.axios.com/2025/05/16/rubio-nato-trump-5-percent-defense-spending-summit-deal