Pixel isn’t a rebrand of Nexus.
The selling point for Nexus phones were that they were relatively affordable yet came with stock android and regular updates. Also, that you had a choice when it came to hardware features and price but could expect the exact same software experience, save for better performance obviously for phones with better specs.
Pixel phones are a way of competing with iPhones even more closely. They’re status symbols, they range from expensive to even more expensive, all have a unified look to them, and Google has become the hardware manufacturer.
The Android One project is probably closer to what Nexus was, IMO.