Especially when looking the older BM bands, most often, it is not phenomena of big cities and capital area. In Finland, most of the relevant bands would come from all sorts of small towns, small cities. Later on, more people would move to Helsinki or such.
I would assume this was partially merely thing that back in the day, bands were often started simply for "having something to do". Possible couple guys really into what they did, and couple friends could be pressured in, who otherwise wouldn't necessary have the passion to do much. Even if bands may not have had any particular worldview against metropolitan qualities & urban, it still had an effect.