The theory was formulated in the 1960s and 1970s as new information was obtained about the nature of the ocean floor, Earth's ancient magnetism, the distribution of volcanoes and earthquakes, the flow of heat from Earth's interior, and the worldwide distribution of plant and animal fossils.
The fact is loose control arm or track bar bushings can contribute to death wobble. Bent, or loose bolts, wallowed out mounting holes, and bent control arms can also contribute to your Jeep catching the shakes. To prevent this, keep an eye on your control arms and track bar.
A grinding noise on braking is usually caused by a lack of brake pad material; the pads and rotors are now metal to metal, with no braking material left. Brake pads are like bars of soap. Eventually they get used up, and you have to replace them and spend a little money.