Why Mobile will decimate certain Enterprise features and applications

Here are two reasons why I think so :

1)  PC sales has been declining for a few years now while mobile sales has been zooming up. In other words the place where data is being consumed is changing. If your products and services are not in that place we will lose out ( like yahoo did).
2) If you think about it, mobile authentication , mobile access and usage can be a DIRECT competitor for Active Directory and ERP user licensing by offering alternative way to access and authentication. Can I can cut licensing , PC and authentication costs if I can use free mobile based authentication and mobile based access of ERP systems ? Yes I can unless ERP vendors decide to change their on-premise pricing strategy.  Think about it......and let me know your tasteful comments.