You cannot make the whole page extension not visible/hidden and enable it dynamically.
You can make a field/control visible or not visible, and that could be made dynamically, which will override any visible/not visible settings made via personalizations.
But it has not be done to all your controls.
Well if you make an app on BC you could make the page extensions hidden if the trial period is over for exapmle. I haven’t found a way to uninstall an app automaticly when the trial period is over.