There are stores trialling exactly your preferred method. One of my local supermarket chains has portable barcode scanners on a wall. You pick one up, scan your groceries as you collect them, then take the scanner to a self checkout that links to the scanner. At that point you pay for your items and leave.
Leave the tinfoil hat on. There is a precedent for exactly what you are describing. When radios went from valve to transistor, radio manufacturers kept the number of transistors low and only slowly increased radio quality over the years. They were able to make higher quality radios from day 1 but didn’t so they could sell more radios.
There are stores trialling exactly your preferred method. One of my local supermarket chains has portable barcode scanners on a wall. You pick one up, scan your groceries as you collect them, then take the scanner to a self checkout that links to the scanner. At that point you pay for your items and leave.