Why did the Rootes advertising executives reduce their children to "luggage" status?
Luggage?  Well, that's what the captions actually said.
Hillman produced 7-seater saloons back in 1935 and 1936, but not in 1946.
Is this their proposed method of carrying the same number of passenges in smaller cars?

Here's a picture and caption from the 1946 Hillman Minx brochure :

LUGGAGE PROBLEM SOLVED More than double the enclosed luggage space on last year's Minx is provided by the new outsize luggage boot.  Lid rises easily to fully open position after catch has been raised.  Special spring- poise arrangement prevents lid falling.  Compartment is illuminated at night, safety red light also shows at rear.  Spare wheel, jack and tool kit are in entirely separate felt lined compartment.

Here's a picture and caption from the 1964 Hillman Minx Series V brochure :

Plenty of room for luggage The full-size, weather-tight compartment provides ample space for your luggage.  The spring-assisted lid needs only light effort to open and it locks securely.  The floor has a protective mat, and the spare wheel is quickly accessible.