“I’m glad I’m in my youth”
The increase in saltiness isn’t as disproportionate as you might think. The first minute or so of cooking is mostly warming the ham and it’s water content up to boiling temp; most of the moisture remains and the saltiness only increases a little. But leave it in for another couple minutes and you’re driving off the water as it evaporates… you can tell the water content is dropping by the increasingly firm texture of the meat, but most of the salt remains.
Bacon is similar. It too gets much saltier the longer you cook it, but not many people actually taste raw bacon to realize how much saltier it gets: raw bacon doesn’t taste that salty. Also with bacon, as long as you cook it slow enough the fat renders out and you’re left with an almost potato-chip of salty meat.