You are telling about developed websites, I'm telling about the need of some extension like .mobi.

cctlds have a specific purpose and they are mandatory for every country to protect the intellectual property and Trade Mark rights of companies and business owners operating from their countries.

What's the purpose of .mobi? Mobile websites can be deployed on any domain names, regardless of extensions. Do you think buying a .mobi domain name, and deploying a mobile website on it will optimize the performance of the mobile website?