I'm getting too old to care what platform (language, framework) other people prefer, but I suspect that if you were to go to any given web development conference, empirical evidence would not square with OS X being "unsuitable" for web development. Beyond that, I suspect you could web development done on pretty much any desktop OS these days. I'm sure you could do web development on Chrome OS, if you wanted to.

This strikes me more as "This is different than what I'm used to!" or "I don't much care for this." than "This is unsuitable." Emacs is available on OS X. Beyond the initial server configuration, I'd say the large majority of packages your average web developer is installing are from NPM, RubyGems, CPAN, etc.

just because it doesn't work for you doesn't mean it's unsuitable. it doesn't work for me either, but i know plenty of people who it does work for. same with windows.

and that said, you can always put linux on it if that's what works best for you

and i always develop in a vm which is as close to production as possible, less surprises come deployment time then. although i know people who don't, so each to his own