Some good answers, but everyone has overlooked the most important and most ‘true’ answer. The fact is that the oceans aren’t getting any saltier any more. They stopped getting saltier many hundreds of millions of years ago and are now at equilibrium. The amount of salt being added to the land directly from the oceans in any year is identical to the amount that is being washed away. And I mean every year, I’m not talking about geological timescales. Salt is lost directly from the oceans to the land without any tectonic pocesses being involved.
Most water that leaves the ocean does so as as aerosol droplets that are torn from the surfaces of waves. That’s quite different to the highly simplified myth taught in schools that water evaporates directly from the oceans. In fact if it werent’t for the aerosolisation of water from wave tips there would never be enough water to make rain.
Now that’s important because it means that ocean water becomes airborne salt and all. It’s not the pure water levaing the ocean that we all got taught in school. The airborne water droplets themselves do usually evaporate and leave the salt behind, but that all occurs after the stuff is already floating in the breeze.
And of course when the water vaporises the salt is still left behind, and it’s still floating around in the breeze. Imagine the entire area over the ocean contains billions of microscopic dust motes comprised of pure salt crystals and you’ve got a pretty good picture of reality. Two thrids of the planet is covered in air laden with salt dust.
Much of that salt dust ends up floating back down into the ocean, but an awful lot doesn’t. it gets blown around in the air and eventualy finds its way into the land.
IIRC the amount of salt dust falling onto land from the oceans amounts to about one tablespoon of salt being added to every acre of land surface every single day. And that amount of deposition is, as far as anyone can tell, exactly the same as the amount being eroded into the oceans.
The entire salt cycle has settled down. What is lost from the land equals what is gained from the sea and vice cersa. Just as with water or carbon or any of number of other nutrient cyclessalt moves between land and sea directly, but in proportional amounts.
That might be abit hard to explain tot a child. It’s hard for some adults to grapple with the idea that water evaporates not directly from the ocean but from slat water droplets floating above the ocean. It’s even harder to ‘believe’ that a few grains of salt are spead evenly over your yard (and roof) yard every day so thinly that they are invisible.
But there you have it. The salt from the land washes into the oceans and the salt from the oceans tuns onto salt dust and gets blown straight back onto the land.
The Great Circle of Life ™.