Can definitely agree they need to be context based, dunno how the situation there is in the US precisely.

I can also say from experience though that no speed limit doesn't mean there aren't tons of overtakes, and speed changes when overtaking isn't possible. Not everyone is comfortable with the same speed. If you have a 6 lane highway without speed limit here, you have trucks going 80 km/h on the rightmost lane, some cars following them at the same speed and other cars going around 100 that often use the rightmost lane too and then overtake every truck. Then cars going around 120 in the middle lane except some go 130 and others 110 so lots of overtakes happen. Then you have the leftmost lane where everything from 140-220 tends to be (def skews to the lower end though) and you can guess the result.

But there's also a cost benefit here ... people may feel comfortable driving at speeds that are more likely to cause deadly accidents. Even if you can drive that fast, the outcome is so bad if you make a mistake, that you shouldn't.