Length and track wasn't as limitated as today, and that made the cars so interesting and different.
(Just put 1973's Lotus 72 and Tyrrell 006 side by side.)
The small front wheel phase of the 70s was over then, and I guess they needed narrower rubber so it wasn't standing in the way of the airstream needed for the sidepod wings.
That's why the front wings went smaller or were completely deleted in these times.