According to ARRI, the concept of developing a digital solution for cinematographers was born due to the 2008 financial crisis. At that time, nobody had money to make movies or buy cameras. Furthermore, there was a threatened strike of the Screen Actors Guild (SAG) that never happened, but it forced productions to use AFTRA actors. SAG actors needed to be used when film cameras were used, but AFTRA actors could be used when the cameras were not film-based. That means shooting digital was the sole option. From that time, ARRI has abandoned the R&D regarding the high-speed version of its 435 that was designed to run at 250 FPS 3-perf, and focused on the creation of digital cinema camera, which was the ALEXA. By the way, ALEXA is a code name for the engineering slot in the development process of the camera, and ARRI has decided not to change it.
Read more: https://ymcinema.com/2020/06/02/arri-confirms-the-alexa-super-35-4k-to-be-launched-in-2021/