In other countries going over the speed limit a small amount will get you fined and your license suspended if you do it by enough or often.
People in countries like Australia have to warn US visitors that they have to keep below the speed limit
Yes, there is an "enough or often" limit in the USA as well. State driver's licenses are based on a point system and too many infractions will result in a suspension of your license if your points dip below a given threshold. Your margin of speed vs limit increases the point deduction. Fines vary down to individual localities, some of them being annoyingly high. In most places (I believe) driving with a suspended license is a criminal offense.
One big difference may be that most places in the USA have been able to resist photo radar/LPR automation of issuing speeding tickets, so the odds generally favor you in most areas until they don't. There's also this tacit allowance for "going with the speed of surrounding traffic". If all the traffic on the freeway is going 10MPH over the limit, you're generally safe in the herd like a zebra.
The USA is a big place with a very diverse set of driving conditions and jurisdictions, so the more you know an area the better you can navigate the character of that area's enforcement. Some places you'll deal with flagrant enforcement pushes at the end of the month as police try to meet quotas. Some places use traffic law enforcement to subsidize their budgets. Our mapping apps can alert us to speed traps if other drivers report them. Drive an area long enough, you'll know where the common speed traps are, and understand the patterns in road design that facilitate them. Generally, we have the luxury of being able to flout speeding laws to such a degree that we can feel indignant when we're caught, but the law is the law.
Sure, when the state wants you, they'll get you. Read Three Felonies a Day: How the Feds Target the Innocent. I'm not one to say otherwise (quite the opposite), but for most people, most of the time, in most of their lives, western legal systems are pretty top notch in protecting people from arbitrary and corrupt application of the law.
In systems that truly embrace arbitrary and corrupt enforcement, it's quite a bit different system than largely objective traffic laws which society has agreed upon but which are rarely enforced (e.g. turn signals, lane merging in intersections, etc.) which turn into selective enforcement. I say this as someone who firmly believes that selective enforcement is ripe for abuse and has inherent problems, but on the balance I prefer the latitude I have as a driver in today's system than one where all traffic regs are enforced through automation at scale (which may be where we're headed in the next few decades, honestly). The reality is that as drivers, we probably curse the fact that these laws aren't enforced more often until we're the ones cited.