Apparently, there is no shortage of 22-year-olds who think that law school is the perfect place to wait out a lousy economy and the gasoline that fuels this system — federally backed student loans — is still widely available. But the legal market has always been obsessed with academic credentials, and today, few students except those with strong grade-point averages at top national and regional schools can expect a come-hither from a deep-pocketed firm. Nearly everyone else is in for a struggle. Which is why many law school professors privately are appalled by what they describe as a huge and continuing transfer of wealth, from students short on cash to richly salaried academics. Or perhaps this is more like a game of three-card monte, with law schools flipping the aces and a long line of eager players, most wagering borrowed cash, in a contest that few of them can win.