Hi. Being a cabinet maker I'm obviously a great fan of wood, but not really as work surfaces that are expected to resist moisture, heat abrasion, oils & fats, tea, HP sauce etc etc.
Basically, they won't. Even with a lot of TLC they won't. That, I'm afraid, is wood for you.
We tend to call these years of use "patina" and pay a fortune for it in antique shops.
I have a table where a hundred years ago somebody put down a hot candle snuffer and scorched the surface. Makes a great tale and adds a good few quid to the value. However I imagine at the time sombody got a good clout round the ear for their carelessness.
Bot much compensation I know, but at least enjoy the moral superiority fact that goes with using a green material naturally finished!