Wi-Fi chips always had "user" program area, in theory anyone could call any of chip vendor, and with NDA, $$$ an 5 years of back and forth, could have met the exact same goal as what you can do today with ESP32, even in 2010. I've seen a Twitter ticker display made from a mPCI Wi-Fi card in a maker meeting back then. The guy demoing it was a company engineer with access to internal docs, wasn't giving it to anyone else.

The genius of Espressif was that they didn't issue C&D letters and DMCA takedowns when people started modifying firmware for their product using garden variety GCC without even asking and then ported hobbyist garbage called Arduino Core. They did initially panic a bit, but soon their management realized it's a golden ticket to something, and they bet the whole company on it. And they got the return they deserve.

There aren't a lot of aspects that are technically so advanced about ESP8266/ESP32. It's just the ones made by the hungriest and most aspiring Wi-Fi chip manufacturer.