Am I Just Killing Trees?

I've got two more packages set to be mailed out to two more theatre companies.  What's in these packages? An 8 by 10 glossy of myself carefully stapled to a properly formatted resume, along with a brief cover letter.  Since October of 2008, right around the time Rabbit Hole concluded at the Gladstone, I've sent out 21 of these little beauties. I have yet to receive a response for any of them. In fact, looking through My Documents, I realize that I have been sending out packages like these since 2006 and I have yet to receive a response to any of those either.

It kind of makes you wonder what's the point?  Does anyone even open my letters? And if they do, what makes it that I am immediately filed under "G" (that's G for Garbage for those who might be unclear).

Is it my lack of Equity status? Is it my photo? My resume? My location in Ottawa? What?

I wouldn't say I'm bitter, I'm more just really curious to know what companies are looking for when they claim to be holding general auditions.  If you have any insight, I would love to hear it.