Our old metal did not benefit from the latest wind tunnel derived super critical wonder aerofoils, capable of lift at impossibly low airspeed. We had to hurtle down the glideslope at relatively high speed just to make them work. High speed=high ROD= low attitude?
Yes, just about right.
These older aircraft did not have especially advanced airfoil sections, and....also did not have leading edge devices nor advanced trailing edge flap designs, so a lower body angle was absolutely needed.
The B-47, just as one example, used quite a clean wing design, no leading edge devices, and single slotted semi-Fowler type trailing edge flaps.
Early B707's...the same.
Later on, with more advanced designs, detailed LED's (and especially, slats) together with double (and triple) slotted Fowler flaps were a great help in keeping approach speeds in check, while at the same time, allowing much greater landing weights, in normal operations.
Higher apparent body angles were the result.