NATO members aren't particularly large customers for American weapons. Poland is the largest, but is dwarfed by Japan, Saudi Arabia and Qatar. Ukraine is receiving a bunch of weapons, but that math isn't so straight forward (they're getting a ton of old stock) and they don't have much choice anyway.
Apart from Patriot, Atacms and a few other modern systems, Ukraine is basically saving the US the cost of destroying old arms
Europeans have spent 80B $ in 2024 and 68 in 2025 on US weapons.
That's not peanuts.