I think a better formulation of the same concept is the following: Web is the new lowest common denominator. The lowest common denominator used to be the shell

I think a better formulation of the same concept is the following: Web is the new lowest common denominator. The lowest common denominator used to be the shell. The one thing you can always depend on being there, and with well-understood standards. Obviously people realized the benefits of more sophisticated graphical UIs, but without one standard UI framework across platforms, you couldn't have a replacement for the general purpose shell. Web technology now provides that standard UI framework, and is programmable/extensible by a vast number of devs without learning some platform-specific or esoteric UI framework. Its a bonus that it also runs on devices that don't have shell access.