Hi Shyamal,
We have been considering this for a while now, and it is currently being tracked as an open feature request. However, it is not something in our current roadmap.
This is not a case of avoiding developing a feature. As any company developing a product must, we have to prioritize developing certain features over others. We would love to implement folders and improve the media library all around as soon as we can. We have many improvements planned for the dashboard and Writing Room, and hopefully work we have been doing in our codebase will allow us to do this at greater speed.
I understand the use-case for having folders; also, search through large numbers of documents can be frustrating and time-consuming. One workaround to group documents is to use the 'Private Notes' feature as described here:
These act as 'Tags' almost and make use of the search function more efficient so that finding media becomes easier.
If/when the team has any more information on this subject, they let everyone know here 
Thanks.