Mostly only IoT devices from Asia. There are a small handful of things coming out of the west on ESP32, but professional users still stay away as they don't have the kind of engineering connections into Wwstern industries that Nordic et al do. That includes sales reps, training, etc etc. The things that matter to large engineering firms aren't really present from Espressif (although I wish them well and the ESP32 is an awesome platform).
Yea, I would assume a large percentage of startups that use Wi-Fi adopt esp32 since it's much easier and cheaper to get up and running compared to the competition.
More established companies don't need to adopt it but I assume it will change as time goes on. Kind of like how Webview or React Native was scoffed at in the beginning but now it's pretty commonplace even at large companies. Or like when Twilio IPO'ed it started targeting larger firms by building out their sales department because at the time it was mainly a hobbyist platform.
Esp8266 doesn't have Flash Encryption, or Secure Boot, whereas Esp32 does and Espressifs SDK ESP-IDF is maturing. So it's definitely going that direction.
Nordic announced its Espressif Competitor but haven't released the cost yet. Espressif seems to be throwing things at the wall to see what sticks (S2, S3, C6, H2, etc). I think their IPO definitely helped them raise more cash to do more things.