Why is foo(*arg, x) not allowed in Python?

Look at the following example

point = (1, 2)
size = (2, 3)
color = 'red'

class Rect(object):
    def __init__(self, x, y, width, height, color):
        pass

It would be very tempting to call:

Rect(*point, *size, color)

Possible workarounds would be:

Rect(point[0], point[1], size[0], size[1], color)

Rect(*(point + size), color=color)

Rect(*(point + size + (color,)))

But why is Rect(*point, *size, color) not allowed, is there any semantic ambiguity or general disadvantage you could think of?

Why are multiple *arg expansions not allowed in function calls?

Why are positional arguments not allowed after *arg expansions?