I've been a Mac user since 2006 when I bought my first Mac: a white MacBook Pro with an Intel Core Duo processor running Mac OS X Tiger. My current Macs are a 2013 MacBook Air and a 2013 Mac Pro, both running macOS Mojave. I prefer macOS to Windows and desktop Linux environments due to macOS's Unix environment, support for commercial software such as Microsoft Office and iTunes, small but essential programs such as Dictionary.app, and the overall fit-and-finish of macOS compared to other desktops. However, from a hardware standpoint, I feel abandoned by Apple. I value user-serviceability and upgradability in my hardware (the only reason I ended up buying a MacBook Air in 2013 was because I still wanted to stay on macOS in the days of Windows 8 and GNOME 3), and I was waiting for two years for yesterday's Mac Pro announcement, only to be disappointed by the pricing of the Mac Pro, which is twice as expensive as the previous model.
Since the demise of BeOS in the early 2000s, there hasn't been any commercial competitors to Windows and macOS in the desktop computing realm other than perhaps ChromeOS. However, unlike the early 2000s when Windows' marketshare was in the 90+ percent range, today there is more diversity of personal computing platforms thanks to the popularity of smartphones, tablets, and Chromebooks. Given this new diversity of platforms in 2019, I am wondering if there is room for a new commercial desktop operating system to emerge, one that attracts users that are frustrated with Apple's direction of the Mac but who don't want to switch to Windows or the Linux desktop.
Linux has a lot of users giving it time and money and even it struggles with driver and other support. There are other desktop projects out there that take Amiga and BeOS and have a decent OS overall, but nobody can use them as serious daily drivers for work (ok, most of us can't). I think there is a lot of room for improvement here, but it's a massive project and so far nothing can touch those big three with the exception of BSD, which is the obvious 4th place I think.
What I really want is a billion dollars to have a brand new Smalltalk or Lisp machine built with great hardware support, graphics, and something like Mathematica builtin to it. Rebol/Red would also be good here.