Just to make you feel better, the readers only come in twice a week. They sift the scripts and the ones they like they take away to read, the rest get enveloped. Once a month the readers meet to discuss the scripts they like.
If they took your script but didn't like it, you still get feedback. Sifted but rejected scripts get the generic letter.
The problem with the writersroom method is that your script is tainted by all the other scripts around it. If you read a lot of shit you get lazy at recognising good stuff, although you think it would be the other way round. For example, I read a sketch on here that i thought was awful. Turns out the writer is pretty much a comedy genius. I realised they were very talented after reading a second piece, but at the time I'd trawled through a lot of mediocre sketches one after the other and my mind was mud.