I'd argue a much more core issue is simply the primitive voting system guarantees a two-party system. The US desperately needs ranked choice voting which would inject diversity into the system, diversity that's necessary for survival.

Any political structure is going to fail when you have a duopoly. One side decides to not play "fair" and bam, everything falls apart. You need to avoid any individual party having full control in the first place. Then the checks and balances can actually function.