Style is what you can get away with.
I understand the rules Astaire and Grant are breaking in the OP's pix but I don't mind.
Flusser is my hero who disappoints most frequently. This usually happens when he tries to introduce a contemporary casual element.
Besides the track suit bottom pic, check his deployment of denim in this video
at about 2:50.
There is a way to wear blue denim with a striped flannel coat, and Polo or Cucinelli has already rigged it many times, and I've worn it myself (with an old Flusser coat even) but here it's just not happening.