Well what if you don’t WANT the interface to change between viewports? We used to use Desktop-style interfaces on 1024x768 displays, or even 640x480. Now we just get a one-dimensional mobile interface when the viewport is smaller than whatever arbitrary threshold is fashionable among designers. It’s incredibly annoying to have interfaces become downgraded (ie hyper-simplified) regardless of what the user requests just because they haven’t kept up with the resolution upgrade treadmill. Pinch and zoom (in BOTH directions) is such a powerful UI tool from the user’s perspective but its usefulness has become completely neutered by insistence on “reactive” design ripping control away from the user.