I think you're underestimating how many creative projects done for clients are very much led by something they've seen before. "Make it like the Tesla site. I love the Tesla site!" At some budget ranges, it's not worth the time to fight that.

And beyond fashion, user expectations are a massive influence. People are wary of right-side navigation, designers know that top-left is the common spot for branding for a reason, etc. There are very practical usability and design reasons that things get pushed down a fixed number of creative paths.