You’re not useless, you’re just misplaced.
Imagine if Apple closed down the iPhone business and started making muffins - the catch is they have to use only what is in their current inventory. Obviously aside from the muffins being disgusting (microchip flavored muffins anyone?), Apple will not appear valuable. It's not that Apple doesn't have value at that point anymore, it's that Apple is not doing what it was built to do. Apple as a technology manufacturer is irreplaceable, but the moment it attempts to step into an ill-fitting role that value can no longer be realized. Apple's pieces of the puzzle don't fit into the world of muffins, but that doesn't make it less valuable that just means it doesn’t fit. Figure out exactly where you belong and appreciate the fact that you were built to master and dominate something - you just have to find out what that thing is. Appreciate what you bring, even if you bring nothing. It just means one of your fellow humankind was built for that specific issue, and you're desperately needed elsewhere.