If you look around the world at the Orbans, the Bolsanaros, the Le Penns, the AfD, etc., you will find that polarization and the rising far right is global. First past the post is not a good thing, but the causes are far deeper.
A past global trend was how the center left parties (Democrats in the US, 2nd International Socialist parties in most of the rest of the world) discredited themselves, abandoning their core constituencies and pushing neoliberal economic policies (in the US, free trade, dismantling welfare, the banking deregulation behind 2008). I think that’s the proximate cause in the rise of the global far right.
The cause of that trend is the inability of regulated capitalism to both provide for everyone AND provide the necessary ever increasing rate of profit.
While there have been stirrings of possible left reformist parties (Sanders, Corbyn, Lula, etc) even those that make it into state power are ineffective at creating a new, stable, political economy.
Meanwhile climate change is haunting the globe and the clock is ticking.