That paper is not too remarkable, it's (1) the first one I found and (2) it uses extraordinarily mild conditions.
The gap between the bench and a commercial factory is immense and there are many areas where people write papers like this for decades but nothing really gets built. I think the usual excuse is that the factory is large enough that it needs to gather waste over a huge area and that transportation of EPS is prohibitively expensive. It doesn't help that styrene monomer is worth only 50 cents a pound, about the same as gasoline.