With every single match counting for world ranking, no team can afford playing anything with B teams now, especially not the teams that aim for a good ranking with regards to OG qualification.
Italy and Serbia can afford it.
Poland and Germany just dont need to lose matches against low ranked teams and there is no many in VNL. They will not lose much points losing to Brasil, USA, Japan or China. Of course all depends of their groups in OQT, if they end up with 3 stronger teams than them maybe they need to count every single ranking points.