It was a marketing campaign ("Switch") during the rise of web programmers and web designers who didn't really know how computers worked, during the hot period of startups when all of them were making a lot of money for the first time and it was sold as a status symbol. Not having a MBP among web programmers was like having greentext among highschoolers.

Now, they didn't know how computers worked because they "didn't have time or interest to worry about that stuff, they wanted something that just worked" it wasn't because they were limited as computer professionals.

And of course, it was unix, so it was at least minimally usable for actual programmers, and then you got homebrew so you had package management and normal software available, and they all started using Linux VMs to run the important stuff, so in the end it was all Linux anyway.

With all that, there was no reason not for it to gradually become a totally adequate environment to work in. Plus you got to buy the exact same thing as everyone in your social group. Talk about the next one like you would talk about the next year of a sportscar model. Have it match your phone. Get excited when they did that yearly thing where they all got on stage and sold the new line, then read Daring Fireball's take.