Comparing the two, you can really see how minimalist the modern stuff is. It has less texture, fewer details (buttons, collars), no patterns (at least from the blog post screenshots).

I think you could argue that some of this is just modern sensibilities and aesthetics, but I think a lot of it is probably just the modern movie industry. Like decisions with modern lighting and how flat things looks in modern movies (to make production more efficient and making adding CGI easier), they probably go with minimalist costumes since they're easier to capture on film, cheaper, and easier to make.