One issue with the mobile view is that it also simplifies other elements, e.g. now you have to open the dropdown to access the categories link, and you cannot make the reply form bigger, and it has no live preview.
But other than that seems good enough for someone who really needs it for some reason. 
I also saw a suggestion to set max-width (e.g. 100%) for .wrap in an old topic How to make my forum view wider? but apparently it doesn’t work anymore, it just moves the messages to the left while keeping the same size.
It’s not about the resolution though, it’s about the screen size (e.g. there are 4K 15" laptops, you have to use scaling to make them usable).