"If I had just one WISH, I'd WISH that all gold and weapons I could WISH for would vanish vanWISH from shops nearby and appear before my feet to fulfill my dreams and WISHES. WISH that would work."
WISHWISHWISH
My players are about to hit level 17 sometime soon, send help
The solution is to make your players afraid of a well-practiced DM that knows how to fuck with powerhungry wishes.
"I wish for an invincible unassailable fortress"
it appears... and then falls directly on top of the player
"I wish for true immortality where nothing can kill me ever ever ever"
granted... in a pocket plane with no way in and no way out
"I wish the final boss was already dead""
player is time-skipped to a far future where the boss is dead and so is everything in the campaign they know or care about
To ensure the factor and keep the wishes reasonable, be sure to insist that the wish magic must be spoken out loud, without pause, and more or less be a single sentence like in almost every example given of wishes in antiquity fiction.
Since it’s cast as an action, it’s good to require a six second cap on the wish.
Edit: also, while they’re admiring the limitation of the wish, remind them to roll of they ever get to cast wish again. If it’s not a lower level spell, there’s a chance they lose the power.
The wish works but there is a nearby weapon manufacturing district. The weapons from the warehouses suddenly appear all around the players. They now have to crawl over a giant pile of pointy weapons. And, the gold landed on the bottom of the pile out of reach.