There are CPUs that have external (including L3) caches; and yes, off die they will have a lower latency. And that is not to mention that a cache topology uses

There are CPUs that have external (including L3) caches; and yes, off die they will have a lower latency. And that is not to mention that a cache topology uses much more power, and not just in the T6 cell itself, there's all the cache handling logic as well. But, it is possible to do; insane but possible.