- Retail 2D codes are being rolled out at scale from next year already in many markets; 2d codes will be on many products in the supermarket. Preparations for this have been ongoing for quite long. Mostly scanners have been ready for this for some time. Most recent hardware should handle all this fine. Scanners that don't handle 2D will rapidly disappear.
- For industrial use, QR codes are already quite common. Use of QR codes is much less about replacing existing bar codes with QR codes and more about completely new uses for QR codes. You are right that most factories won't do invasive changes in their setups unless there's a good reason. But efficiency improvements tend to be a good reason.
I was at the Logimat fair in Stuttgart earlier this year. Lots of companies demonstrating scanners, sticker printing, camera modules, and all the rest. There are a lot of companies actively pushing all sorts of solutions around 2D codes.