As long as there is enough physical silver available at or near the "paper prices", the "game" can go on and on. I won't mention "manipulation" as a factor because as long as a person can buy silver at or near the paper prices, then the "manipulation" really isn't a factor. Comex contracts are still being delivered to those who demand delivery (no defaults yet- despite what the BS pundits claim).
You will know when the "game" is over when the paper price for silver is one thing, and the actual price for getting physical metals is much, much higher. We are not there yet and even during recent silver shortages at the retail level, orders were being placed for new metal by the dealers from the wholesalers, and those orders were easily filled for generic bullion and even gov bullion without much delay (which is now available at even lower premiums - like the many ASE sales recently).
Two things will cause PM's to go way up, one is if for some crazy reason regular folks and the ultra wealthy (NON PM bugs) decided to buy physical silver in great amounts that overwhelmed supply (for long periods, not a few weeks), or two, if the "groups" who have been shorting paper silver for 4 years decide to flip direction and "manipulate" the price up with excessive leveraged paper trades in the long direction, which is just the opposite of what they do now and have been doing. I believe industrial demand will stay steady or perhaps drop a little in the near future, but if "investment" demand ever took off, that could be a factor affecting supply. I don't believe though that has ever happened in the modern silver history (that is, excessive physical demand outstripping supply over an extended period).
I don't think the 4 year price drop in silver is due to a glut of metals in storage houses, which is just the opposite it seems to the oil markets, where crude is running out of places to store it in some instances.
Just my opinion.
Jim