This was a strategic masterstroke. By removing the price barrier, Apple effectively accelerated the adoption rate of the new OS overnight, unifying the Mac user base. It paved the way for the "services" era we live in now, where the OS is a loss leader to get you into the ecosystem.
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Mac OS X Mavericks 10.9 was released in 2013 and was the 10th major version of the macOS operating system. It introduced several new features, including improved performance, enhanced security, and a more intuitive user interface. This was a strategic masterstroke