Linear progression can be done forever, it's just the time it takes to progress might take a bit longer. For example, adding weight every workout to adding weight every week, to adding weight every month to adding reps , to adding sets. Periodization is still a useful tool and as Mo noticed, one might progress quickly if they swapped between linear progression and periodization every so often.
Training log: http://muscleandbrawn.com/forums/showthread.php?t=15881
"No citizen has a right to be an amateur in the matter of physical training…what a disgrace it is for a man to grow old without ever seeing the beauty and strength of which his body is capable." – Socrates
"I never saved anything for the swim back."
"Compound exercises, kids! Compound exercises!"