What is the actual reason that most big tech companies give no feedback? Is it just to avoid wasting time and having to deal with a potentially disgruntled cand

What is the actual reason that most big tech companies give no feedback? Is it just to avoid wasting time and having to deal with a potentially disgruntled candidate? I would be happy if they at least sent an email from a no-reply address giving a list of feedback and then ending the discussion there.