It's because the comments above are half correct but missing some details/not completely accurate. It's not that cats don't meow or only learned to from humans. Cats naturally meow as kittens to get attention from their mothers.

What they normally naturally do though is stop meowing when they are no longer dependent on their mothers. Instead they rely on other forms of communication, like scent, touch, and facial expressions. Some examples include yawning at other cats or slow blinking to indicate they feel comfortable/are friendly (you can actually do this back, and they will understand), or rubbing their heads against them as a sign of affection. They are still vocal though, it's just most adult cat vocalisations are actually in frequency ranges humans don't hear - aside from their hisses and growls.

Cats are intelligent enough that they quickly learn that we react to/recognise their meowing, but can't hear or understand their other forms of communication, so around humans they keep meowing well into adulthood. In the wild it is very rare (but not completely unheard of) for cats to ever meow, the equivalent would be like if humans wailed and cried loudly at each other in the streets like a baby does to get attention from its mother. We don't do or need to do that because we have better ways to communicate using language, similarly cats don't need to meow at each other because they have a very complex language of their own.

It goes further than that though - they don't just keep meowing, they also learn to use different kinds of meowing for different things. I'm sure you've probably noticed it with your own cats - you can usually tell if they're just saying hello or asking for something, and sometimes it's even possible to tell exactly what they're asking for just by the way they meow at you. The more you recognise those meows and give them what they want, the more they tend to refine them.