The value of AI companies is speculative just like the railroads were. Railroads also have real value. But you have to have everything ready to use those railroads to make money, or they're just steel bars in the dirt and a big loud heavy thing that moves along the horizon. Too much speculative investment in the railroads (in part) led to the panic of 1873, because just having a promise of a return isn't the same thing as having the return.