“Brand new I could hear minimal road noise, now it is excessive. The tire shop owner mentioned that cupping could cause noise, then said mechanics would have noted cupping if it were there???”
In all likelihood, you have developed irregular wear (what the mechanic says was cupping), and this is usually caused by misalignment and aggravated by insufficient rotation preactice and insufficient inflation pressure maintenance. The first symptom you get is noise, followed later by vibration (depending on how sensitive you and your car are) and then you’ll see the wear pattern.
Try rotating your tires and see if the noise changes. If it does, get an alignment and hope the new positions will get rid of the wear pattern that is already there.