How does the shared single core impact the application vs having a dedicated core on the original ESP32? Also, why did they move to a single core, as I've seen

How does the shared single core impact the application vs having a dedicated core on the original ESP32? Also, why did they move to a single core, as I've seen a die shot of the ESP32, and the cores were only a fraction. 90% of the die went to RAM and the radio.