I agree with most, but, on ph there are considerations as to when it is or isn't needed. In soil, unless your water or nutrient solution is way off, your right. But. water from the tap can be WAY off, I've seen mine hit 8.2! AND, I've seen mine kill plants quickly! outdoor plants are not a valid comparison, their "pot" is unlimited... any ph adjustments they do are very minor, spot tweaking. In a restricted envirnoment, even organic soil can take a dip in ph that can cause problems, there is no predicting what a soil micro-ecosystem will do, they get sick too.
Ph'ing soil itself? Yep, waste of time. You see the signs in soil in plenty of time to just feed water at 6.8 to 7.0 until the issue resolves. There's no fixing a damaged plant, so flushing the soil is a waste of time, flushing causes an already damaged plant to starve when it NEEDS nutrients!
I ph all my water. Is it worth it? Damn right it is! I'd have 4' plants giving me 5 grams dry if I didn't......