You would know that...you're such a wealth of knowledge...I imagine the design team at Ford considered a lot of things noted above, and then promptly ruled them out for one reason or another, but mostly cost. Most "trucks" from that era are pretty sparse in the amenities department.
Usually I agree, but today I'm going to take the other side.
I blame Product Management arrogance, and Engineering hubris. Let's take an obvious example. In 1966, the Bronco rear axle was specified to use the 28 spline shaft. The design, complexity, and implementation of the 31 spline shaft had already been implemented in the C4AW-B Nodular performance axle. So the 31 spline axle was available, and dare I say would cost zero incremental dollars to implement.
But here's what happens. Some pinhead Product Manager in some obscure division, (Like drivetrain engineering) says things like: "28 spline is adequate for a 2800 lb axle in a station wagon..." and justifies it with some engineering study and years of know-how. So the poor guy in design engineering just specifies the inadequate hardware. Then some guy in reliability testing says: "Hey...these axles are breaking." and the guy in Drivetrain says: "no they aren't..." And the product manager says: "I don't know..." and some freshly hired engineering manager transplant from Philco, or Delphi, or Magna says: "Good enough is more than good enough." And the product ships. Then the guy in durability testing says, "We are seeing early axle failure under harsh conditions." and the idiot in the drivetrain group says: "Well they should be ordering the 3300 lb axle" and then everybody recommends the big bearing housing, but the shafts still twist off. Then the warranty guy says "wow, we are seeing a LOT of failures..." and 11 years later, the axles are still too small.
Funny thing is that it is still happening 50 years later. Google "2021 F150 Max Tow 3/4 float recall with no end in sight..." and "lets add the 24-25 models to the list..." That axle costs MORE than the semi float that it replaces. So Ford spent more to get worse...