If the stuff gets added much later than page load (like, pretty much every big Angular page I've seen), then yeah it gets added too late to be sent to the screen reader. It sounds like live regions is what you want but I know at work, due to Angular sucking donkey balls, they've put aria-live="polite" on the body and there's just so much stuff getting changed and added at a snails' pace that it doesn't read out nicely