When it comes to profits, subprime lending ain’t what it used to be. That’s the message being delivered by executives at some of the company’s top players, as well as some midsized ones in recent investor briefings. “2004 was clearly a challenging year for the mortgage market, with market contraction, margin compression, and competitive pressures affecting every player,” said John Robbins, CEO of American Mortgage Network, in a recent conference call. …