Pharo is based on Squeak 3.9, not 3.10. We don't re-implement the kernel, at least not for now. The current focus is on cleaning up and removing stuff we are not interested in (like toys), and providing a stable basis for professional use.
And in 3.11+ we will be looking to borrow improvements from Pharo, without sacrificing backwards compatibility. This means we will likely trail Pharo, but there is no reason why some level of compatability at the kernel level cannot be maintained.
For those interested in following any 3.11 progress discussion, the release@lists.squeakfoundation.org mailing list is open.
Keith