There is no ruse. Putin absolutely subscribes to a certain Russian nationalist view that led to this invasion.The whole thing is a ruse to bankrupt Russia while lining arms contractor’s pockets.
Is the US and Europe trying to bankrupt Russia? Well sure, because Putin decided to be an asshole. There's nothing logical about his decision either, it would be much better to just sit back and make bank on the good thing he had going.
Will it enrich defense contractors? Sure! War always does. Hell, look up Civil War weapons, lots of familiar names there, they made bank back then too.