The decision to select an IDE can take place at many different levels of an organization. A single engineer may be using the IDE for just one project. In this case, they're likely to simply select whatever they're familiar with or whatever happens to ship with the microcontroller unit (MCU) for that project. At the other end of the spectrum, an entire department could be integrating the IDE into their development workflow. In this case, the decision could affect dozens of engineers and address multiple target platforms for years down the road.
Some engineers prefer no IDE at all—instead, they'll pull together their favourite text editor and a command-line compiler or linker (such as GCC or Clang), handcraft some makefiles, and set off with coding. This is a perfectly valid approach, too—it will result in a great amount of...