That doesn't seem unlikely to me, since Trump has destroyed the basis of trust with his allies and is thus doing considerable damage to one of the few US industries that is still functioning well, namely the arms industry.
Perhaps he somehow thought that Europe would buy the weapons needed to equip itself because he has unilaterally terminated NATO protection from US companies. Maybe a few that you can't get anywhere else, but the EU would be incredibly stupid to buy from a nation that is now hostile to it.
So other buyers will probably have to be found - although Russia has its own arms industry and is also on good terms with China. Moreover, unlike Trump, Putin really isn't an idiot.
But hey, maybe the EU can negotiate a billion-euro arms deal with Russia to get better conditions for Ukraine.
It would hardly be any different from buying weapons from the US.
That's true, but he will still need new buyers because his previous allies, whom he has alienated greatly, will very likely reduce their order volume considerably.
I think that this so-called statesman, with his petty power games, has once again overestimated himself on this issue - as with others issues but in the same stupid manner.