Many of the early virtual teams were strictly project based and it was taken for granted that their lifespan would be limited.  But as virtual teamwork has become more commonplace with participants becoming more adapt to working virtually using technologies that continue to set new standards, there is a good likelihood that organizations will not hesitate to build permanent Global Virtual Teams - and some already are.
Recognizing that there has been little research conducted about businesses creating permanent global virtual teams, some researchers from VIA University in Denmark and Northumbria University in the UK decided to look into it. Their working paper,  Managing Geographically Dispersed Teams: From Temporary to Permanent Global Virtual Teams  makes a good argument that organizations will come to rely on building permanent Global Virtual Teams in the coming years.  Considering the expanding trend towards globalization and “with organizations outsourcing and building networks with partners; with organizations joining through mergers and acquisitions across national boundaries; organizations will have to – or have already – established lines of reference between dispersed team members in permanent organizational structures.”
The study takes a look at some of the challenges and how solutions and new perspectives are evolving in areas such as the managerial and leadership responsibilities. As was referenced in the paper,  “Whether you call it self-leadership, emergent leadership, shared leadership or transformational leadership, we believe that virtual teams provide a unique opportunity for redefining the concept of leadership.” (Zigurs 2003)
The paper also provides some useful practices such as suggesting that, “leadership responsibilities for Global Virtual Teams include formulation of clear mission, team roles and the specific task; timely and regular feedback to build team trust and commitment; handling of conflicts between local and global responsibilities and deadlines; defining right mix of technologies to be used; promotion of self-leadership and team empowerment; and being a knowledge sharing role model.” As the virtual working environment continues to evolve along with technology we’ll see current challenges progressively overcome and the notion of permanent global virtual teams common place and not so remarkable in the future.
You can link to the entire paper here: Managing Geographically Dispersed Teams: From Temporary to Permanent Global Virtual Teams