I work with a mid sized engineering consultancy.
We began switching to ESP as our primary platform just around 2 years ago, just as wifi gadgets were starting to boom.
To date, we got 500 megs of MCU project in our repo. Though most of code is repetitive, there is no chance we will part with such a huge codebase.
Being able to complete a $200k project in a few weeks through code reuse, instead of few months is huge, and imagine how it is for bigger companies with own hardware. No chance anybody switching now.
No. It was first comer advantage in affordable wifi MCUs since they existed just fine before but only as more expensive solutions as I mentioned. You can keep on claiming otherwise but the facts don't support you in claiming that there weren't wifi MCUs before.
Technically, and conceptually they were hopelessly behind an integrated WiFi MCU.
Espressif did not innovate in the technology space but in pricing and having enough documentation available that hackers could piece together an open source toolchain and libs for the chip.
No. Espressif is used because it is _cheap_ and has relatively good support libraries. Just the chips/modules from other vendors are usually 15 to 20€ in single quantities while you can get an ESP8266 minimum development board (almost all normal arduino boards are minimum development boards) for like 3€.
Unless other vendors reach that same level, they will always stay back.