The curvature puts space in front of the toes while holding the foot in place. If shoes followed the actual shape of the foot, all your toes would bump up against the front of the toe box and you'd end up with blisters or bruised toenails or both.
Wrong.
1, the toe box isnt what holds your foot in place, at least it shouldn't be. Also to do that it would need to be touching your toes which makes no sense to your statement.
The mid foot is where your shoes should hold you and maybe the heel, but around the heel are sensitive nerves and of course your achilles tendon, so mostly the mid foot.
2, proof that you're wrong are several minimalist or 'barefoot' brands or models like vivobarefoot, altra, lems, Xero shoes, Merrell(trail glove, vapour glove), new balance minimus, freet.
All of which have foot shape design, the widest point being the big toe, mimicking the shape of a natural healthy foot(if you want to see one of those look at people who have spent their lives barefoot).
Most shoes/boots begin curving in from the ball/last big toe knuckle, NOT from the end of the big toe, hence it pushes your big toe inwards potentially causing a bunion and a host of other problems.