Prices CAN be manipulated. But they can't be manipulated for a long term. If the underlying fundamentals don't support the price, the market will find out.
Folks who speculate, trying to ride the trend can get burnt this way. The "smart money" tends to get out before the bubbles pop. Be it real-estate, energy prices, or whatever.
I do agree that markets can be manipulated. I simply don't agree that it can be done on a long term basis.
When they are manipulated, then when they correct, they typically correct enough to cancel out the manipulated price.
Oil was very high back in 08, IIRC and then crashed. It stayed very low, lower than it was before it went up.
Had it not been manipulated, the market may have been happy to stay closer to where it was. Instead, the bottom fell out and we enjoyed lower prices for quite a while.