Rejected petition Employers MUST reply to all Applicants

I have applied for several jobs now, and not heard back from any. I feel it is disgracefull that a job will not even contact you to tell you what you did wrong and why you did not get the job, it causes a lot of time wasted waiting for that call or email, just a simple email is all I would want and it sickens me that companies dont care enough to do this. They say they are to busy to answer back if lots apply, so what? The information they give us could help us do better when applying for a other jobs so I think it is worth their time and to be honest how long does it really take? Just a breif email would do telling you the outcome and where you went wrong, is that so much to ask?
I feel their should be a law in place which demands that an employer must reply to ALL applicants regardless of their success this would boost the moral of people who are finding in employment who just simply dont get anything back from an employer when applying and so they just end up giving up.