This was an expected step of the evolution of the Memory Hierarchy. RAM is just bigger-but-slower CPU cache. Swapfile is just bigger-but-slower RAM. There's always a trade-off between size and speed.

Incorporating RAM into the CPU package gives a big performance boost at the expense of maximum capacity. To compensate for the reduced performance in tasks that require more memory, you can either add another layer into the Memory Hierarchy (i.e. CPU Cache -> Fast RAM -> Slow RAM -> Swapfile), or you can improve Swapfile speed. It appears Apple have done the latter - they claim their SSD is up to 2x faster.

Video game consoles have done something similar with the latest generation. Only a 2x increase in RAM from the last generation (compared to an 8x/16x increase from the generation before), but a focus on storage performance.