Without the builtin radio it's really hard to justify the use of an ESP32 over, say, an STM32. The integrated small package with "everything" to make a fun project is the whole appeal.
I don't think they do IP theft from STM32 (if it's even possible at current node size). They have very thorough datasheets different from STM32 ones and their own SDK with unique code (although it seems to be inspired by STM32 libraries, but absolutely not theft).