Why Do We Still Need Microcontrollers?

A developer is asking why microcontrollers such as Arduino, ESP8266, and ESP32 remain necessary when computers and smartphones grow more powerful each year, noting that most embedded and IoT applications only need to read sensors, drive motors, switch relays, or send data over Wi-Fi. The developer points to microcontrollers' small size, low cost, and low power draw as key advantages, and asks whether rising interest in edge AI and edge computing will push microcontrollers to become more capable or see them replaced by more powerful processors.

Computers and smartphones are becoming more powerful every year. So I've been thinking about a simple question: Why do we still need small microcontrollers like Arduino, ESP8266, and ESP32? Compared with a computer, a microcontroller has very limited processing power and memory. Yet they are used everywhere in IoT and embedded systems. One reason is that most embedded applications don't need a powerful computer. A device might only need to read a sensor, control a motor, switch a relay, or send some data over Wi-Fi. Microcontrollers are also small, inexpensive, and consume much less power. But with Edge AI and edge computing becoming more popular, devices are getting more capable. So I'm curious about the future: Will microcontrollers continue to become more powerful and capable, or will more powerful processors eventually replace them in many embedded applications? I'd like to hear what others working with IoT and embedded systems think.