I was wrong on Trump every step of the way, so you won't find me saying that O'Leary can never win the leadership, let alone become prime minister. 

However, in the two and a half years until the next election, a lot of momentum in the the 'drain the swamp' movement could evaporate - Trump could unwind (likely), Le Pen and other nativists in Europe may not succeed at the polls (very possible), and Brexit will be a done deal and may yet prove a disaster (quite possible).

Of course, I could be wrong on all of those as well :)