Linux has a 'nerd only' baggage with it from ages
Mac is more polished compared to Linux (and its hundred flavors which add to the confusion).
Good points there.
The "nerd only" baggage has somewhat gone away with Linux distros like Ubuntu, Mint etc, which have made Linux easier for people to use.
However, yes, the main problem I see with Linux is the availability of so many distros, which creates a lot of confusion. Add to that, there are different desktop environments, different types of packages, etc. Moreover, the distros themselves are very inconsistent. If one version of a distro works well, you can't be sure if the next version will. I have seen people distro hopping a lot, going from one flavor to another. That does not work for me. I want consistency and stability. I don't like to change things often. This is the same with many people.
Further, I have used some distros, and they somehow don't look all the polished to me. I am not satisfied with their look and feel. It often feels like I am using something old.
People want things to work out of the box, and this is where Windows excels. You don't have to change much in Windows. Things just work out of the box. With Linux, there's no such guarantee, and you might have to make a lot of changes, before you are satisfied.
Then, there's the problem of drivers and software. One of my main reasons for not migrating to Linux have been these. I have need for all kinds of software, and many of these either won't be available for Linux, or I might have to spend a lot of time to search for them, or, they won't be of that quality. Then, there's drivers. My webcam wont work on Linux, and I have to search a lot for how to make it work. If such a simple thing won't work out of the box, people will just move away.
IMO, Linux should do away with so many distros, or, focus on making things universal across all distros, so that these things get polished and work over long periods of time. They need to be consistent, and work out of the box.
There are however distros like Linux Mint, which are easy to use, and will serve the purpose for any general user who just wants to browse the internet, or watch movies, listen to music, etc.
Some people have migrated to Linux, or are thinking about this since this onslaught of Windows 10, and its issues. Still, it will be long time before Linux can become mainstream given its state of things.