I’m not so sure. I’m from a multi-party democracy, and while the ultra-rich (or, well, mega-rich I suppose - the US’s ultra-rich are at a different level I think) certainly have their interests catered to, I feel like on balance the scales are tipped to their benefit to a way smaller extent, largely thanks to the multi-party system.
What country? Virtually every liberal democracy is currently experiencing a far-right resurgence right now, with similar themes of austerity and lower taxes on the rich. Multiparty democracies, especially those with parliamentary systems, have greater immunity, but they’re all suffering from the same disease because they have the same foundational flaws.
In the EU, but my point is that the scale is way different. I’m in the Netherlands, and the far-right resurgence here is still being kept in check to some extent by the other parties. I shudder to think what would happen if they could do what they want just because they’re the largest, but they can’t.
The Netherlands has extra immunity beyond just the political system by way of a strong social safety net as well. Fascism thrives on poverty and resentment. But keep in mind, the Netherlands is practically the perfect example of social democracy and yet still the far-right is able to find a foothold to power. The Netherlands does a great job treating the symptoms of capitalism, but the foundations can still rot.