That does not change the fact that the various Linux distros have been oversold and underdelivered. Starting a year ago there was a steady drumbeat of how great Linux was, and then a following stream of dissapointed people who attempted to use it.
Yes, it may all be the same kernel, but the intefaces all have different and confusing terminology. Linux users have made their point loud and clear of how they disdain "proprietary" drivers and even to the point of making their use more difficult and then complain that manufacturers don't support them?
One thing that is not mentioned is that the foundation of Linux, GNU is only a few years younger than DOS, which was released in 1981 (while GNU was released in 1983), and Linux itself is only a few years younger than Windows which was released in 1985 (Linux released in 1991).
Linux seems to work well in areas that have significant IT support, but in the consumer area, only if you happen to have the equipment that happens to be widely supported. Then we have the comment that there is a large number of supporters on the forums. Yet, when I posted a question about wireless on the Ubuntu section of the Linux forum, I received exactly one response in three weeks. That was by another user who had the same problem and had received information, later confirmed, that our wireless chips were a problem, but so were many others. The solution was to buy an add in wireless connector and hope that it was supported. That's not a solution. My solution was to go back to XP.
If you are using a machine connected to the internet though a connection via ethernet, and do not need to read/write an files with a Windows machine, then you have an easier time getting it to work. If you want it to interface with currently existing windows based machines it becomes difficult and if you want to use wireless with that, good luck.
As to Linux distros being primitive, it is. Maybe not in what it is capable of doing, but in trying to install things. I can download an application in Windows, double-click it and it will install because of the Window's installer. Try that in Linux and it just sits there. You have to find the application in a "package" that your flavor of Linux supports and bring it down.
If all those who support Linux would get together and write a manual for Linux in understandable terms, and get all the developers of the 31 flavors of Linux to use common terminology and spend more time solving the lack of drivers rather than accentuating the Linux differences, it may have a better chance. You make the comment that the various distros differ only in their interface, you need to point that the interface which you are referring to is the internal interface to the kernel as well as the user interface. That is why different distros not only look different, but behave differently as to installing items.
And then there are all the applications that are not supported in Linux. Of course the refrain is that there are applications that do the same jobs. But, not interact with the primary ones like Citrix, which is used in business, not some terminal emulators used to interface with mainfram computers. Then the linux horde crys "who uses mainframes anymore" - most of the Fortune 500. If you want someone to shift to your OS, you need to support their apps.
In the time that the Open Source committee has been working on this (25 years) they have actually lost market share to the hated Microsoft. After all, in 1983 there were questions about whether MS-DOS would have a majority market share. Then they worked with major CP/M applications to finish the porting of those apps from CP/M to DOS, plus all the new DOS apps and the rest is history.
I get the feelings that despite their statements, the Linux developers do not actually want to improve their market share. They are perfectly happy have the small pond, better to be a large fish in a small pond, rather than a small fish in a large pond.