By 1996, we had found our economic footing, were starting to pay down the budget deficit and the perception was infinitely better than it had been four years prior.
Perot surged because his populist message hit a cord with Americans who had been ravaged by the Reagan Recession. However, with America out of a recession, our economy growing again and a fairly popular president, the mood in the country was rather status quo.
In fact, 1996 was a pretty boring election. Most incumbents won - Republican & Democrat. Voting turnout sucked (it was 10 points or so lower than it had been in '92) and generally, Americans just weren't angry anymore.
So, Perot's campaign never gained traction. Plus, his erratic behavior in 1992 (announcing, then pulling out and then getting back in late in the game) turned off a lot of voters.