As previously noted, I can't see much future for these high-end 8051s - because, at this level, Cortex-Mx seems an obvious choice.

There really is no point in trying to fight 8051 restrictions (with stuff like banking, etc) any more - just go straight to a Cortex-Mx!

But I think the 8051 still has plenty of life in the small applications where even Cortex-Mx is still over-specified.

And, of course, there will always be specific cases where the specific features of the 8051 give it the edge in a specific application - Richard has at least one example...