This is how Jeroen Domburg, Espressif Technical Marketing Manager, addressed this matter in a post on hackaday.io:

"We actually never intended the CPU architecture to be part of the name, as for 99.9% of all users, it doesn’t matter: you write your code in C or some other language, and the compiler plasters over any difference in ISA. Available peripherals, supported radio protocols and CPU power and memory are more important."