After many years I was back in the job market earlier this year. I ended up writing to 6 carefully-chosen companies. I got responses back from 5 of them, interviewed at 4, and got job offers from all of them.
The fact that you applied at 50 places is a bit of a deceptive statistic, because first of all, there's no way you carefully crafted your initial contact to each one.
At each of the places I contacted during my job search, my initial email was very carefully worded. I spent about 3 hours writing and revising one fairly short email, to make sure it conveyed exactly what I wanted.
If you just send a generic form letter to a company, they're going to give you the same consideration you have given them: very little.
Even if you did tailor the email to each company, there's no way you as a candidate are going to appeal to more than a handful of the companies, because they all have their own quirks and cultures. NOBODY is a viable candidate for 50 different Ruby-oriented companies.
Also, no offense but I have to concur with other comments here that your writing may have had something to do with it. If what you sent them was worded at all like what you've posted here, then you probably lost a lot of potential responses because of that.
If you want to get your foot in the door at a company, the first impression you make is everything. Sending a poorly worded email is a surefire way to shoot yourself in the foot.