Thanks for your video. This no doubt foreshadows the Raspberry Foundation eventually moving away from the Broadcom SoCs to their own custom SoC for future Raspberry Pi iterations as well.
This makes a ton of sense. The GPU IP will be the tricky part. Will they build or buy?
If they're sticking with ARM I would bet on them using an ARM Mali GPU, since they would almost certainly be licensing the microarchitecture from ARM anyway.