I'm guessing the economies of scale didn't allow Talgo to spend a lot of time and money in design. They were prepared to bring their existing
Talgo XXI design to the US, but the FRA regs made that impossible. With only two small orders in the US and zero orders in Europe, Talgo didn't see much point to spending money on a team of industrial designers and engineers.
There are plenty of Loewys and Dreyfusses out there, but they're not working in rail. Good design adds value, but manufacturers don't need to do much when there's so little competition in the US market. This also means that there is no organized opposition to FRA's regulations.