The expectations in the first debate for Trump were really low and the expectations now are even lower. If he manages to keep his ego in check for just two hours during this Sunday's debate, prepare a little bit and doggedly focus on key Clinton negatives (trustworthiness, secrecy, ambition, foreign policy and of course the emails
), he could do some damage and regain momentum. So theoretically, it is not too late.
But since we are talking about Trump, a Reality TV candidate, with no ideology, policy, morals or purpose, then the answer is a resounding
YES - it is too late. Trump was never realistically going to win and he certainly won't win now. As I said several times here, it is a testament to Clinton's fundamental weakness as a candidate that Trump is even still competitive.