True... Steering components are more breakable than just a solid
steel axle.
Not outright because of that, but rather there are more
components with a steerable axle than a fixed one... Just like a
'front axle' have a lesser loading capacity than a 'rear axle', in
terms of vehicles like the O405 or O530.
A vehicle that has a larger capacity steerable axle would be
mid-engined vehicles like the B10/12M. Engine weight tends to shift
forwards especially when braking and hence the front axle has to
cover more weight than a conventional rear engined vehicle.
Trucks have the most versatile loading axles, all axles are
designed to support large amount of weight.