You're ignoring how they got to be 90% of the market. It is a comforting lie to say that it was all shady business practices and marketing, though those certainly played a role. Here's a clue:
"One of the things, none of the distributions have ever done right is application packaging ... making binaries for Linux desktop applications is a major fucking pain in the ass. You don't make binaries for Linux, you make binaries for Fedora 19, Fedora 20, maybe even RHEL5 from 10 years ago. You make binaries for Debian Stable…well actually no, you don't make binaries for Debian Stable because Debian Stable has libraries that are so old that anything built in the last century it doesn't work. …and this [“Don't Break Userspace!”] is like, a big deal for the kernel, and I put a lot of effort into explaining to all the developers that this is a really important thing, and then all of the distributions come in, and they screw it all up. Because they break binary compatibility left and right."
"One of the things, none of the distributions have ever done right is application packaging ... making binaries for Linux desktop applications is a major fucking pain in the ass. You don't make binaries for Linux, you make binaries for Fedora 19, Fedora 20, maybe even RHEL5 from 10 years ago. You make binaries for Debian Stable…well actually no, you don't make binaries for Debian Stable because Debian Stable has libraries that are so old that anything built in the last century it doesn't work. …and this [“Don't Break Userspace!”] is like, a big deal for the kernel, and I put a lot of effort into explaining to all the developers that this is a really important thing, and then all of the distributions come in, and they screw it all up. Because they break binary compatibility left and right."
--Linus Torvalds, DebConf 2014