The TGV Duplex was developed in the 90s, and continues to be developed, the new version (avelia horizon) coming out in a couple of years. There's a reason it us

The TGV Duplex was developed in the 90s, and continues to be developed, the new version (avelia horizon) coming out in a couple of years. There's a reason it uses a locomotive ("powercar") concept, it relates to it being a double-decker (which all the other trains you mentioned aren't. I believe the Acela replacement (avelia liberty) uses powercars as well.