They are now doing the same thing with iPhones. 12 and 12 Pro were identical phones. 13 and 13 Pro are identical phones. Yes, there are differences in cameras, but that's really about as far as the difference goes.
- record-breaking numbers are upgrading from multiple previous models
- smartphone market is still growing
- there's a non-negligible number of people going for the "shiny new thing"
They were selling record-breaking numbers when they only had a "pro" and a "non-pro" model, too