Do you believe that having an old domain can help you to get better ranking for your desired keywords?
So why some of new domains can compete with old ones in some cases?
I think Google keeps on changing/modifying ranking algorithms. The only time an old domain can help is if it has back-links. If it was just parked, that's as good as a new domain. But you do benefit, if your domain name has the keyword(s) included.
old domains are always better than new domains. Old domain can bring faster results with less efforts. In some cases new domains compete with old domains, because those new domains contain more quality back links than old one