By Dan Weil ‘We always believed these past two years represented a fake bull market, built on sand, not concrete,’ the prominent economist David Rosenberg says. Stocks are slumping, with the S&P 500 down 18% year to date. And prominent Wall Street economist David Rosenberg says the carnage isn’t over. “We always believed these past two years represented a fake bull market, built on sand, not concrete,” he wrote in a commentary on MarketWatch. “We also remain steadfast of the view that the inflation scare is going to pass very soon.” Among the bearish factors are a “collapse” in money-supply gr…