It’s not a small chance. It’s a very, very real and reachable chance.
Further, if successful this year, there will never again be a ‘conventional Republican candidate’. The face of the party has changed, and new coalitions are opening up. The more savvy among the left understand this, and are very, very afraid of it. The Democrats are looking like the ‘old’ party with ‘old’ ideas. Politics is very much about emotion, and the Democrats ‘feel’ old and stale, not to mention the corruption they have to try to explain.