It's hard to imagine a mechanical voting system being adopted today that's worse than America's system. The state-level districting make first-past-the-post local elections worse. The electoral college is strictly worse than just weighing state votes the same way, a relic of needing to send physical people instead of, ya know, just getting on the phone and adding the (very small electoral vote count) numbers from the states.
But imagine the country in a 2x2 of trust:
The top row trusts Republican leadership. The bottom row doesn't. The right column trusts Democrat leadership. The left column doesn't trust Democratic leadership.
The square that trusts nobody generally assumes everybody is rigging everything as much as they can. And if you think this way, obviously you shouldn't change the voting system. Whatever system we have at least sort of balances power between the main parties. If they want a change, you probably won't like it.
The people trusting only Republicans and distrusting Democrats have been accusing them of voter fraud and election rigging. Of course you don't want to change the way we're doing things – any change opens up potential for unfamiliar and even harder to detect fraud!
And if you trust Democrats and not Republicans, would you want to have Donald Trump change the nature of democracy in America?
If you trust every politician (which is, wow, huh), then you probably don't see election reform as a super high priority, and would probably agree that, super divisive times where casual accusations run rampant isn't a great time to optimize.
If we were starting from scratch, there's lots to improve. There are systems that are proportional while maintaining local rule, that sounds good, if you want more legislation, that is. But more doesn't mean better, so something that just barely works has a lot going for it.