Had Perot not been paranoid--remember he was surging in the polls before he pulled out--and then reentered, but with no where near the support before the paranoid event, ending up with only 19% of the vote;--he could have really rattled the dentures of the major parties.
The other problem that Perot had--which Trump would not have had--is that he could not speak extemporaneously on television, but looked totally spaced out, reading off a teleprompter behind the camera. I have personally used TV for half hour speeches in a campaign and can attest the effectiveness, if one can extemporize.
The reason to keep the Third Party option viable, is the changing demographics, that the Left is counting on to make Conservatives a permanent minority. A strong and articulate candidate, who lets the mindless acceptors of Leftist premises split their vote between the Democrats and the sort of "Republicans," who prattle their own version of the same acceptance of Socialist values, just might pull it off.
No! I am not suggesting that that is the ideal approach at this point. But a strategy on that order, might prove our last resort, if we cannot recapture the Republican Party next year. (And keep in mind that even if we do, a Cruz nomination might well provoke a Corporate CEO 2016 version of Republicans for Johnson, such as the Rockefeller branch of the Party hit Barry Goldwater with in 1964.)
The problem is complex. So we have to keep all options open.
Plus, another historical note. Teddy Roosevelt's Bull Moose Third Party, which actually outpolled the Republican Party in 1912, lost to Wilson==but the mere threat of a revival by Hiram Johnson or William Borah was the whip that kept Henry Cabot Lodge from cutting off the debate that the irreconcilables finally won to defeat Wilson's League of Nations; leading to the overwhelming landslide of 1920.
Yet, all of that said, I sincerely hope that the useless idiots in our party--as I remain in the Republican Party;--those who keep hamstringing our efforts, will wake up and stop acting like amateur Nazis trying to suppress dissent. They have no sense, no integrity or courage, and no future.