The whole App Store / iTunes archipelago, the willful rejection of expandable and [easily] user-serviceable hardware design in favor of a 'form before function' approach, the related planned obsolescence strategy [e.g., older hardware simply will not run recent software; new OS breaks older 3-party software], and the ghastly overpricing were among the factors that drove me off.
Mainly, I liked MacOS because I prefer putting work into projects as opposed to maintaining my own system, and MacOS "just works," until it doesn't. These days though, I run an idiotresistant distribution of Linux on my productivity machine, a minimal one on my 'learning' machine, and am generally more content. Also, running Linux, I feel less like I'm directly interfacing with a villain from 'Black Mirror'