As dumb as selling shoes, an item that comes in 100s of sizes, over the internet.
As dumb as expecting people to find a date or a spouse online.
As dumb as building an encyclopedia that anyone can edit.
You get the idea. Electric cars with 100-mile range, vegan hamburgers, milk made from oats, free college courses…
The next breakthrough is almost certainly going to be something really dumb. Or perhaps merely obvious and unoriginal.