It has to do with the absence of robust front-lines in modern warfare.
This absence is less related to a supposed rise of 'irregular' warfare than to decreased force densities (my opinion, obviously).

The fights of today are similar to encounters with hostile stragglers in WW2 or with red infiltrating infantry in Korea (IMO).

Years ago I reasoned that armoured trucks make only sense for mechanised brigades and convoys which attempt to supply them - the trend towards armouring everything will likely end in a few years when large quantities of vehicles need to be replaced.