These days, larger MCU manufacturers will generally provide access to a free IDE to help lower the barriers to entry for potential developers. Historically, these IDEs didn't offer much more than a compiler and were generally pretty terrible to work with if you were using them daily. However, in the past few years, there's been a shift to higher quality vendor-supplied IDEs, as chip manufacturers try to differentiate themselves from their competitors. Sometimes, they have extra features integrated that will help configure hardware and/or vendor-supplied drivers, which can be helpful during hardware development, initial board bring-up, and early firmware development, where hardware peripherals are being exercised and integrated with the rest of the system.
Since these tools aren't the core business concern of a hardware...