Whether it's Michelle Rhee demanding that arts instruction be reserved only for fluent readers or ten hour day charter schools with nary a minute for painting, the education reform movement is no fan of the arts in education.
This is not especially surprising. It's not just the focus on test scores. Nor is it solely a capitalist impulse against harder-to-monetize subjects or corporatist education focused on creating the service workers of tomorrow.
It's also that the education reformers who taught didn't teach long enough to teach the arts.
This is not hard to understand. If you are a lightly-trained new teacher, you're going to teach subjects for which you are given the necessary materials. Almost every teacher gets a full classroom set of math and reading materials - workbooks, alphabet cards, anthologies, and so on. The materials are ready for you to use and easy for the harried and overwhelmed teacher to access.
Even easier to teach? Test prep. Every low-performing school is awash in practice tests, test strategy guides, computer-based testing, and test-taking curricula. These are usually scripted, and typically based on a direct instruction model: you talk and the kids test.
Early in one's teaching career, when all teachers are learning how to manage a classroom, procedures, school policy, materials, assessment, and procedures, direct instruction with very clear instructions is a lifesaver.
Arts instruction, on the other hand, is a nightmare of preparation and management for the new teacher. The materials are not provided, and a lot of planning is necessary just for getting the supplies to the students (let alone using and cleaning up the supplies). Alternative certification programs do not cover arts instruction; teachers will have to find or create activities themselves. Untrained first- and second- year teachers are unlikely to be able to handle arts activities - and if they are disposed to consider the arts of minimal importance anyway, they won't try.
An example: if I want to teach a reading lesson on phonemic awareness, I group the kids together. They sit quietly and respond to my oral prompts, which I can come up with on the fly (words that start with a certain letter sound, rhyming words, etc.). Everyone starts and finishes together and the materials needed are minimal (at most, maybe some tiles for counting sounds).
If I want the class to watercolor, first I need to source the materials: paint, paper, brushes, cups for water, rags or paper towels for spills, and a place to dry the paintings. I then need to figure out how to pass out these materials to the class, what to do when water becomes too saturated with paint and needs replacing, how to handle spills, what to do when some kids finish early...
And that's just procedures and management. If I want the paintings to delight the artists, I will probably also need to figure out how to teach using watercolors: how to get bright, saturated tones, how to layer colors, how to make colors bleed into each other, and so on. (At the least, you will want to teach the first of these, since it will save you the hassle of sopping wet, grayish masterpieces.)
Teaching the arts gets easier when you know how to handle a classroom. After a couple of years, every plastic tub you empty at home comes to school to be repurposed for holding watercolor water. You know how to get the cups emptied after the project with as few spills as possible. And knowing this, you can plan a neat lesson for your class.
Early on, it's very hard to do this. (This is why I invite new teachers over for shared crafternoons in my room.) The difficulty is such that even when teachers try arts instruction, things are likely to go poorly - and that makes it harder to try again.
But if you're only in the classroom for a couple of years, you will never gain the experience necessary to have cool arts activities. And without it, you cannot understand why it is so vital to children's education. And should you go on to great things in education reform, it will be very easy for you to cut the arts out entirely.