If I'm not mistaken a very significant part of that is due to hobbyist interest in the chips, not in the least by Sprite_tm (also a HN user, now employed by Espressif).

The ESP8266 essentially started out as a wifi modem, responding to AT commands transmitted over serial, but going from there to a full standalone device relied on a lot of work by enthusiasts[0] and a leaked proprietary SDK[1].

[0]: https://hackaday.com/2014/09/06/the-current-state-of-esp8266...

[1]: https://tweakers.net/reviews/7992/community-interview-sprite...