I suspected he would lose when he was recently visited and supported by Vance. Nobody likes Vance (in Europe, and probably anywhere). Getting prominent backing by an unlikable character isn’t a winning strategy.
Also, the fact of faking a terror attack and everybody just shrugging it off as an obvious Russian false flag op. I think even Orbán understood at that point that the jig was up.
One thing that's surprised me over the last few years is how much Russia messes with global politics. It seems to seeping into public consciousness so instead of being seen as a bit of a conspiracy theory you now have the crowds shouting Russia out. I don't know if that'll effect other Russia backed projects like Brexit financed by Russia via Arron Banks and Trump, financed by the "We have all the funding we need out of Russia" stuff. It doesn't seem illegal but the voters may be getting fed up with it all?