My bad for not clarifying this in the article. These 32 cores will according to the rumors be high performance cores.

Apple will not be increasing the number of slow cores, as that would make no sense. They will keep the 4 slow cores they have.

Scaling the memory is not an issue. I have discussed this with people familiar with chip design, which have all said thas is not actually much of an obstacle. The M1 chip is still quite small.

Adding external RAM would not necessarily cost performance. This is like usage of cache. Slower storage devices generally don't pull the system down as much as it would look due to caching. You could think of this as simply adding one more layer of RAM.

We already see this in how they use their SSD disks. With M1 they are basically using them as extra memory and it works remarkably well because they are so fast.