Absolutely true! the soil must have certain basic elements and food available for microbes. However, most all the papers I've read state fairly unequivocally that when not interfered with, assuming well-mineralized soils, microbes *and* plants can play a huge role in determining/adjusting soil pH in the rhizosphere, which is where all the action we're after happens, yes?
Yes, with organic fertilizers you can over-fertilize, but if you focus on feeding the soil this will almost never happen. ;) Mostly, pay attention to Ca.