"unless you have an in with the employer or manager."

That's usually the key point. I have a number of friends without college degrees that do just fine. Their usual modus operandi is to meet someone from the company at a conference, consult for them for a while, and then get hired once the company sees how awesome their work is.

I wish this weren't needed, but hiring managers function under conditions of very low information, and they wade through too many resumes of low quality to avoid filtering it on some criteria. Degrees and GPA are the most easily quantifiable filtering criteria, and so that's what makes it into the filtering software.