Saying "Quality is always a trade-off" implies you can't actually make things better over time. I would accept something like "You can always trade off of the quality you are capable of producing to reduce costs", but the point is that capability can in fact change, and thus there are ways to improve quality that may not be a trade off (because they also improve the business/system along other dimensions). Even simple little things like aligning a process with the intended outcome can reduce costs while improving quality, you don't have to invent a revolutionary method of manufacturing.