I think its more about semi-realistic space usage though i think a more generous range would be better ie a tanning rack could be outside.. whereas forge related upgrades need to be somewhat close as molten steel,copper etc needs to be hammered quickly and bellows for fires etc also need to be close. but these too could have a slightly bigger radius. ps my workaround is to build a shelf above both and place a few upgrades above . to save floor space :-)