As far as graphics go, there are a few companies that tend to dominate, and they throw a lot of effort into their products. I love GIMP, but I won't pretend that it's equal to Photoshop - there just aren't enough developers working on GIMP to compete. Krita, on the other hand, is open source and it's hard to beat; I doubt you'd find many in the industry that hate it.
Blender's situation is a bit more complicated. A lot of people just don't like using it. The Blender developers don't always focus on industry needs. There's not really a solid roadmap for features, and the direction can change on a whim. That doesn't suit the big or medium studios very well. Blender has better feature parity with the mainstream commercial 3D suites than GIMP does to Photoshop, but if you rely on certain commercial plugins that don't have equivalents for Blender, or you need functionality the devs aren't focusing on, you're not going to choose Blender.
Support is also a reason people choose commercial software, although it's a faulty one as you can buy support for most large open source apps. You've got a better chance of getting bugs fixed in open source software than in commercial software. The perception that open source has no support is pretty widespread, though.
Open source adoption is a lot wider in other areas, such as IT, software development, and high performance computing.
tl;dr Open source has its strengths and weaknesses. Graphics isn't an area it's particularly strong in.