TMX is not ISO 400. It's not even 200. It's rated at 100 and many people think closer to 80.
And I think you missed the part where we were talking about sheet film. Delta 400 is not available in sheets. It used to be - I still have some from the 90s frozen though I haven't tried it to see how well it has kept. IF Kodak were to cancel TMY-2 then Ilford might reconsider making Delta 400 in sheets.
If they'd make XP2 Super in sheets like they used to make XP2 many of us would LOVE that, and there'd be another 400 speed sheet film.