In high use brakes the whole hub, wheel and even axles act as...

In high use brakes the whole hub, wheel and even axles act as part of the heatsink and initial heat is dissipated by lighter weight vented. design.

Lighter solid brake can only take so much heat and cycles before distortion and high wear depending on materials.

Unsprung weight also has issue of bush and joint wear as well and yes rerated springs and shocks would lead to better dynamics. As you know most off the shelf trucks are barely safe in some mine specs without a load on.

Othe rconsideration on site is that GVM is so poor in some trucks and axel loading that by the time that have abash plate, bullbrt, winch and towbar safety kit, rollbar and a parts back on tray they are at max capacity let alone a extended diesel tank.

Not trying to be negative , just realistic knowing some equipment site mechanics and constraints and accountants.