The vast majority of buildings do follow the same regional templates though.
The reason they’re not specifically concrete cubes is more to do with the relative unpopularity of brutalist design than it is to do with the artistic flair of architects.
In fact I’m sure most architects would love to stamp more of their creative personality into their work but they have to dial it back for cost and practicality reasons.
Here in my area of Belgium it's become very popular to build modern cube buildings. Flat roof, featureless. No longer brick but a flat white, grey or black outside. i find it absolutely disgusting.
We're really just reinventing brutalism but without much of the commendable outcrops like the barbican or whatever.