cash - OK let's talk long term then...
Maybe if we break down the indexes into their component stocks it will clear things up...
In the oils, let's take the biggest issue - XOM (now happens to have a bigger market cap than any other company on the planet) is selling for ten times earnings and just signed a major contract with Libya. (we all know what happened when Occidental drilled there) It has enormous un-tapped proven reserves in the Beaufort Sea and elsewhere. XOM is about to double it's earnings as it's p/e also doubles, which indicates a four-bagger for XOM's stock price.
On the other hand, the biggest tech stock (no longer biggest market cap) - MSFT has a p/e that is twice as high, and nothing but law-suits and a flight to Linux in it's future. If it's earnings are halved and the p/e is halved, it will lose 75% of it's value (best-case scenario)!
Maybe we should hedge ourselves by going long XOM and short MSFT. In any case it would be foolish to assume that in the long run, their price performance will be similar! JMHO