Here in Germany, it's common to weigh goods that are priced by weight and then have a sticker printed out to stick on them for the cashier. I don't see printing a QR code or whatever weird mechanism Amazon uses to price items being much more complex
This would run afoul of commerce laws in pretty much every US state. Tare must be set from zero, not relative to whatever happens to be on the scale, and certainly not on the fly.
Another huge regional grocer, HEB, does this in Texas with their largest and most upscale stores, and it's been a norm for nearly a decade.
Alternatively, the entire shelf is a scale, but the shelves are smaller so that only one person can pick vegetables at a time.