GrapheneOS won't survive the next generation of devices because bootloader unlocking will also go away (>>44765939 ), and without kernel security updates that OS can't continue.
Now there's also no more sideloading, so what purpose does Android even serve anymore?
Because Google-free AOSP-derived Android distributions are far more versatile, offer far more freedom, impose far fewer restrictions and tend to end up being far less expensive than whatever the fruit factory decides their dedicants have to use today. If Google goes the way of the fruit folks and AOSP no longer offers these freedoms the next step is not to surrender to the Church of Apple but to find a way to evade those restrictions.