Switching to a different creative software solution is a much bigger task than just buying the new license and installing the program. You have to relearn basic tasks that are second nature in the other thing, change workflows due to different file formats or you might just not have the option to because the rest of the industry depends on the competitors software. This is true for individual professionals as well as big companies, where switching to a different software package also means dropping efficiency for a while and hiring people to teach your employees your new software. This is a step that no company will ever take and Adobe has recognized that and taken away the only opt-out of paying them assloads forever, which was buying a perpetual license and staying on that version.