Everyone's forgetting how weak Bush was. Perot didn't beat Bush; Bush beat himself. Perot's candidacy provided an alternative for angry Republicans...and without Perot, a majority of those angry at Bush would have stayed home.
"Read my lips, no new taxes."
^^^^^^^^^^
Bush 41 was at a low point in his presidency in 1992. From the bar code readers in NH, the Buchanan fight, the lack of conservative support, all the way through the summer campaign, he was not connecting with the voters. A wide spectrum of voters were prepared to stay home if they found no alternative to Bush.