Google has confirmed the vanilla Pixel 8 will get Gemini Nano in the next Pixel Feature Drop scheduled for June 2024. Currently, it is exclusive to the Pixel 8 Pro. https://www.notebookcheck.net/Google-Pixel-8-to-get-Gemini-Nano-later-this-year.819804.0.html
So there you have it, on-device AI functionalities that require more of everything to work as designed is just another ploy to get people to upgrade their device - amazingly enough, AI fails to attract and retain beyond the initial entertaining moments, most people just don't care at all.