Very true thats why server market penetration for linux is high. In fact linux is not just great for servers its also great for lightweight embedded devices such as home routers, industrial equipment as well as very popular devices like the Raspberry Pi.
If you want simple toys, it works well.
As it happens I use a FDT Perimeter made by Ziess every day at work. It runs an embedded Ubuntu. I love the fact that the mouse pad stops working or the pointer moves everywhere but where you want it, at random times..reboot, and lose the test data. Wonderful.
As it also happens we use a custom Linux for our patient record cards, appointments and accounts. We've discovered a new feature: press two keys-any two keys, in quick succession and the terminal gets covered in garbage. F4--> F10-->exit, re-enter your lost data at your earliest convenience.
As it happens we also have an OPTOS UWDS and Canon Fundus Camera that run XP. Never lost data. Never needed top re-boot due to a system wobbly. Not ONCE in 3years
Thats why , just like windows there are different flavours of Linux , eg Red-Hat and Centos for the server and Ubuntu or Mint on the desktop.
They are just eye candy on top a kernel. The underlying behaviour is the same and not built from the ground up for a desktop.
And the GUI is often inconsistent and poorly thought out. On out mains system we use a KDE variant. The task bar has a digital clock in the corner. Click on it and Calender shows up. So far so good. I see all 7 terminals with the calendar showing. Why? Umm: "How do I close the it" is the reply. Well just hit the cross button....there is no cross button! Click on the desktop? Nope. Eventually after random clicking all over the screen and by chance on the digital clock, it closes. Brain dead design.
Amateur is a very loaded term, it suggests that you are not aware that Linux is a multi-billion dollar industry. It suggests that its not built by paid professionals such as those employed by IBM, RedHat, Canonical and Cisco plus many others. Or perhaps Google who use the Linux kernel as the basis for its operating systems Android and their Desktop ChromeOS. Android has the lions share of the mobile operating system market , greater than iOS and others combined. Thats pretty impressive for what you describe as an "Amateur" os.
Oh please the average user isn't downloading anything made by IBM, Redhat, Cisco. And a major reason why they choose the Linux kernel-and that's all they're doing- is because they don't have to be held hostage by Microsoft's licensing, and they make billions of dollars "maintaining" the systems they sell.
Most users are not aware that they have Linux as a choice.
Enough do for their to be more using it than actually do.
That is because Microsoft actively penalize OEM manufacturers for offering it as an option. Finally any new version of a desktop oriented version of Linux running on supported hardware eg: Ubuntu , is every bit as capable for every day simple things* without going anywhere near a command line.
* Web browsing, email, word processing, image processing
No, its not every bit as capable. And you're only one crappy little update from booting up in a full screen command line. Good luck when that happens
There is actually one other thing thats holding it back , and thats people like you propogating the myth that people seem to think that an operating system that can do all the things above and more is no good for the desktop.
No-on is holding it back.
Its holding itself back.