God I would kill to make the pipe dream of competition in the OS space happen, there are many interesting hobbyist projects like this that just peak at some of the features and ideas that the current dominant operating systems don't touch.
Graphics is just incredibly complex, opaque and obtuse kernel-space logic with tons of corner cases.
Web browsing for normal day-to-day usage is about a million lines of code, +/- one order of magnitude.
Porting a web browser to work on your platform (chromium, webkit) doesn't require rewriting the whole thing, and chromium etc already are designed in a way to isolate browser code from OS-specific code (as we can see by chromium code for windows/linux/macOS/android being mostly shared).
On the other hand, making it so your OS works with the large number of common USB devices, networking chips, etc... it's a fantastical effort which linux only barely manages to accomplish.
But the overwhelming mass of devices to drive is the show-stopper. Probably the best that can be done is to implement drivers for Qemu virtual devices, and run under a hypervisor that has drivers for real things.
A 1.0 launch really doesn't need to support everything. It just needs to support a large enough handful of common devices. Hell, Apple OSes barely support any hardware.
Except when they are, which is anytime something is poorly documented, which is pretty much all the time. Let's not even get started on vendors who don't WANT you to write drivers for their hardware.
> Hell, Apple OSes barely support any hardware.
Would be interesting to see an OS target specifically Apple HW to make it a bit easier on the devs.
If that's not documentation, I dunno what is. Each of them will be wrong, of course, but they're all likely to be wrong differently, so you can learn from the differences.
Note though that at the same event, a few days earlier, a hobby OS was presented which ship with its own ex-nihilo web browser implementation: SerenityOS [0]. There is still a lot to go but apparently they have:
1. A lot of resources (dozens of active developers).
2. A plan (meaning organization, resources, tooling, etc).
It's still a hobby thing but it's promising.
[0] https://awesomekling.github.io/I-quit-my-job-to-focus-on-Ser...
An OS is only a means to run software. Nothing more.
So, mostly three. Especially considering the BSDs' wide server presence.
I think you can accurately say that there are either two or five distinct operating systems in wide consumer use at the moment: Windows and Unix, or Windows, macOS, iOS, Android and Linux.